diff --git a/src/plugins/lib/holidays.xml b/src/plugins/lib/holidays.xml
index c9dd98b89..68606d44a 100644
--- a/src/plugins/lib/holidays.xml
+++ b/src/plugins/lib/holidays.xml
@@ -5,12 +5,6 @@
   <country name="United States">
     <date name="New Year's Eve" value="*/12/31" type="National" />
     <date name="New Year's Day" value="*/1/1" type="National" />
-    <date name="Inauguration Day" value="1997/1/20" type="National" />
-    <date name="Inauguration Day" value="2001/1/20" type="National" />
-    <date name="Inauguration Day" value="2005/1/20" type="National" />
-    <date name="Inauguration Day" value="2009/1/20" type="National" />
-    <date name="Inauguration Day" value="2013/1/20" type="National" />
-    <date name="Inauguration Day" value="2017/1/20" type="National" />
     <date name="ML Kings's Birthday" value="*/3/mon/jan" type="Secular" />
     <date name="Groundhog Day" value="*/2/2" type="Secular" />
     <date name="Lincoln's Birthday" value="*/2/12" type="Secular" />
@@ -22,91 +16,19 @@
     <date name="April Fool's Day" value="*/4/1" type="Secular" />
     <date name="Arbor Day" value="*/-1/fri/apr" type="Secular" />
     <date name="Earth Day" value="*/4/22" type="Secular" />
-    <date name="Daylight Saving begins" value="1999/4/4" type="Informational" />
-    <date name="Daylight Saving begins" value="2000/4/2" type="Informational" />
-    <date name="Daylight Saving begins" value="2001/4/1" type="Informational" />
-    <date name="Daylight Saving begins" value="2002/4/7" type="Informational" />
-    <date name="Daylight Saving begins" value="2003/4/6" type="Informational" />
-    <date name="Daylight Saving begins" value="2004/4/4" type="Informational" />
-    <date name="Daylight Saving begins" value="2005/4/3" type="Informational" />
-    <date name="Daylight Saving begins" value="2006/4/2" type="Informational" />
-    <date name="Daylight Saving begins" value="2007/3/11" type="Informational" />
-    <date name="Daylight Saving begins" value="2008/3/9" type="Informational" />
-    <date name="Daylight Saving begins" value="2009/3/8" type="Informational" />
-    <date name="Daylight Saving begins" value="2010/3/14" type="Informational" />
-    <date name="Daylight Saving begins" value="2011/3/13" type="Informational" />
-    <date name="Daylight Saving begins" value="2012/3/11" type="Informational" />
-    <date name="Daylight Saving begins" value="2013/3/10" type="Informational" />
-    <date name="Daylight Saving begins" value="2014/3/9" type="Informational" />
-    <date name="Daylight Saving begins" value="2015/3/8" type="Informational" />
-    <date name="Daylight Saving begins" value="2016/3/13" type="Informational" />
-    <date name="Daylight Saving begins" value="2017/3/12" type="Informational" />
-    <date name="Daylight Saving begins" value="2018/3/11" type="Informational" />
-    <date name="Daylight Saving begins" value="2019/3/10" type="Informational" />
-    <date name="Income Taxes due" value="1999/4/15" type="National" />
-    <date name="Income Taxes due" value="2000/4/17" type="National" />
-    <date name="Income Taxes due" value="2001/4/16" type="National" />
-    <date name="Income Taxes due" value="2002/4/15" type="National" />
-    <date name="Income Taxes due" value="2003/4/15" type="National" />
-    <date name="Income Taxes due" value="2004/4/15" type="National" />
-    <date name="Income Taxes due" value="2005/4/15" type="National" />
-    <date name="Income Taxes due" value="2006/4/17" type="National" />
-    <date name="Income Taxes due" value="2007/4/16" type="National" />
-    <date name="Income Taxes due" value="2008/4/15" type="National" />
-    <date name="Income Taxes due" value="2009/4/15" type="National" />
-    <date name="Income Taxes due" value="2010/4/15" type="National" />
-    <date name="Income Taxes due" value="2011/4/15" type="National" />
-    <date name="Income Taxes due" value="2012/4/16" type="National" />
-    <date name="Income Taxes due" value="2013/4/15" type="National" />
-    <date name="Income Taxes due" value="2014/4/15" type="National" />
-    <date name="Income Taxes due" value="2015/4/15" type="National" />
-    <date name="Income Taxes due" value="2016/4/15" type="National" />
-    <date name="Income Taxes due" value="2017/4/17" type="National" />
-    <date name="Income Taxes due" value="2018/4/16" type="National" />
-    <date name="Income Taxes due" value="2019/4/15" type="National" />
-    <date name="Ash Wednesday" value="1999/2/17" type="religious" />
-    <date name="Ash Wednesday" value="1999/2/17" type="religious" />
-    <date name="Ash Wednesday" value="2000/3/8" type="religious" />
-    <date name="Ash Wednesday" value="2001/2/28" type="religious" />
-    <date name="Ash Wednesday" value="2002/2/13" type="religious" />
-    <date name="Ash Wednesday" value="2003/3/5" type="religious" />
-    <date name="Ash Wednesday" value="2004/2/25" type="religious" />
-    <date name="Ash Wednesday" value="2005/2/9" type="religious" />
-    <date name="Ash Wednesday" value="2006/3/1" type="religious" />
-    <date name="Ash Wednesday" value="2007/2/21" type="religious" />
-    <date name="Ash Wednesday" value="2008/2/6" type="religious" />
-    <date name="Ash Wednesday" value="2009/2/25" type="religious" />
-    <date name="Ash Wednesday" value="2010/2/17" type="religious" />
-    <date name="Ash Wednesday" value="2011/3/9" type="religious" />
-    <date name="Ash Wednesday" value="2012/2/22" type="religious" />
-    <date name="Ash Wednesday" value="2013/2/13" type="religious" />
-    <date name="Ash Wednesday" value="2014/3/5" type="religious" />
-    <date name="Ash Wednesday" value="2015/2/18" type="religious" />
-    <date name="Ash Wednesday" value="2016/2/10" type="religious" />
-    <date name="Ash Wednesday" value="2017/3/1" type="religious" />
-    <date name="Ash Wednesday" value="2018/2/14" type="religious" />
-    <date name="Ash Wednesday" value="2019/3/6" type="religious" />
-    <date name="Easter" value="1999/4/4" type="religious" />
-    <date name="Easter" value="2000/4/25" type="religious" />
-    <date name="Easter" value="2001/4/15" type="religious" />
-    <date name="Easter" value="2002/3/31" type="religious" />
-    <date name="Easter" value="2003/4/20" type="religious" />
-    <date name="Easter" value="2004/4/11" type="religious" />
-    <date name="Easter" value="2005/3/27" type="religious" />
-    <date name="Easter" value="2006/4/16" type="religious" />
-    <date name="Easter" value="2007/4/8" type="religious" />
-    <date name="Easter" value="2008/3/23" type="religious" />
-    <date name="Easter" value="2009/4/12" type="religious" />
-    <date name="Easter" value="2010/4/4" type="religious" />
-    <date name="Easter" value="2011/4/24" type="religious" />
-    <date name="Easter" value="2012/4/8" type="religious" />
-    <date name="Easter" value="2013/3/31" type="religious" />
-    <date name="Easter" value="2014/4/20" type="religious" />
-    <date name="Easter" value="2015/4/5" type="religious" />
-    <date name="Easter" value="2016/3/27" type="religious" />
-    <date name="Easter" value="2017/4/16" type="religious" />
-    <date name="Easter" value="2018/4/1" type="religious" />
-    <date name="Easter" value="2019/4/21" type="religious" />
+
+    <date name="Easter" type="religious" value="> easter(y)" />
+    <date name="Ash Wednesday" type="religious" value="> easter(y)" offset="-46" />
+    <date name="Daylight Saving begins" value="> dst(y)[0]" type="informational" />
+    <date name="Income Taxes due" value="*/4/15" type="national"
+	  if="date.weekday().__cmp__(4)-1" />
+    <date name="Income Taxes due" value="*/4/16" type="national"
+	  if="date.weekday() == 0" />
+    <date name="Income Taxes due" value="*/4/17" type="national"
+	  if="date.weekday() == 0" />
+    <date name="Daylight Saving ends" value="> dst(y)[1]" type="informational" />
+    <date name="Inauguration Day" value="*/1/20" if="(y - 1980) % 4 == 1" type="national" />
+
     <date name="Passover" value="2005/4/24" type="religious" />
     <date name="Passover" value="2006/4/13" type="religious" />
     <date name="Passover" value="2007/4/03" type="religious" />
@@ -114,6 +36,16 @@
     <date name="Passover" value="2009/4/09" type="religious" />
     <date name="Passover" value="2010/3/30" type="religious" />
     <date name="Passover" value="2011/4/19" type="religious" />
+    <date name="Passover" value="2011/4/19" type="religious" />
+    <date name="Passover" value="2012/4/7" type="religious" />
+    <date name="Passover" value="2013/3/26" type="religious" />
+    <date name="Passover" value="2014/4/15" type="religious" />
+    <date name="Passover" value="2015/4/4" type="religious" />
+    <date name="Passover" value="2016/4/23" type="religious" />
+    <date name="Passover" value="2017/4/11" type="religious" />
+    <date name="Passover" value="2018/3/31" type="religious" />
+    <date name="Passover" value="2019/4/20" type="religious" />
+    <date name="Passover" value="2020/4/9" type="religious" />
     <date name="Assistants' Day" value="*/-1/sat/apr" offset="-3" type="Secular" />
     <date name="Cinco de Mayo" value="*/5/5" type="Secular" />
     <date name="Armed Forces Day" value="*/3/sat/may" type="Secular" />
@@ -125,27 +57,6 @@
     <date name="Parents' Day" value="*/4/sun/jul" type="Secular" />
     <date name="Labor Day" value="*/1/mon/sep" type="National" />
     <date name="Grandparents' Day" value="*/1/mon/sep" offset="6" type="Secular" />
-    <date name="Daylight Saving ends" value="1999/10/31" type="Informational" />
-    <date name="Daylight Saving ends" value="2000/10/29" type="Informational" />
-    <date name="Daylight Saving ends" value="2001/10/28" type="Informational" />
-    <date name="Daylight Saving ends" value="2002/10/27" type="Informational" />
-    <date name="Daylight Saving ends" value="2003/10/26" type="Informational" />
-    <date name="Daylight Saving ends" value="2004/10/31" type="Informational" />
-    <date name="Daylight Saving ends" value="2005/10/30" type="Informational" />
-    <date name="Daylight Saving ends" value="2006/10/29" type="Informational" />
-    <date name="Daylight Saving ends" value="2007/11/4" type="Informational" />
-    <date name="Daylight Saving ends" value="2008/11/2" type="Informational" />
-    <date name="Daylight Saving ends" value="2009/11/1" type="Informational" />
-    <date name="Daylight Saving ends" value="2010/11/7" type="Informational" />
-    <date name="Daylight Saving ends" value="2011/11/6" type="Informational" />
-    <date name="Daylight Saving ends" value="2012/11/4" type="Informational" />
-    <date name="Daylight Saving ends" value="2013/11/3" type="Informational" />
-    <date name="Daylight Saving ends" value="2014/11/2" type="Informational" />
-    <date name="Daylight Saving ends" value="2015/11/1" type="Informational" />
-    <date name="Daylight Saving ends" value="2016/11/6" type="Informational" />
-    <date name="Daylight Saving ends" value="2017/11/5" type="Informational" />
-    <date name="Daylight Saving ends" value="2018/11/4" type="Informational" />
-    <date name="Daylight Saving ends" value="2019/11/3" type="Informational" />
     <date name="Columbus Day" value="*/2/mon/oct" type="Secular" />
     <date name="Ramadan begins" value="2006/09/24" type="religious" />
     <date name="Ramadan begins" value="2007/09/13" type="religious" />
diff --git a/src/plugins/lib/libholiday.py b/src/plugins/lib/libholiday.py
index 4570da273..b399b5d19 100644
--- a/src/plugins/lib/libholiday.py
+++ b/src/plugins/lib/libholiday.py
@@ -49,6 +49,44 @@ def g2iso(dow):
     # ISO: MON = 1
     return (dow + 5) % 7 + 1
 
+def easter(year):
+    """
+    Computes the year/month/day of easter. Based on work by
+    J.-M. Oudin (1940) and is reprinted in the "Explanatory Supplement
+    to the Astronomical Almanac", ed. P. K.  Seidelmann (1992).  Note:
+    Ash Wednesday is 46 days before Easter Sunday.
+    """
+    c = year / 100
+    n = year - 19 * (year / 19)
+    k = (c - 17) / 25
+    i = c - c / 4 - (c - k) / 3 + 19 * n + 15
+    i = i - 30 * (i / 30)
+    i = i - (i / 28) * (1 - (i / 28) * (29 / (i + 1))
+                           * ((21 - n) / 11))
+    j = year + year / 4 + i + 2 - c + c / 4
+    j = j - 7 * (j / 7)
+    l = i - j
+    month = 3 + (l + 40) / 44
+    day = l + 28 - 31 * (month / 4)
+    return "%d/%d/%d" % (year, month, day)
+
+def dst(year, area="us"):
+    """
+    Return Daylight Saving Time start/stop in a given area ("us", "eu").
+    US calculation valid 1976-2099; EU 1996-2099
+    """
+    if area == "us":
+        if year > 2006:
+            start = "%d/%d/%d" % (year, 3, 14 - (math.floor(1 + year * 5 / 4) % 7)) # March
+            stop = "%d/%d/%d" % (year, 11, 7 - (math.floor(1 + year * 5 / 4) % 7)) # November
+        else:
+            start = "%d/%d/%d" % (year, 4, (2 + 6 * year - math.floor(year / 4)) % 7 + 1) # April
+            stop =  "%d/%d/%d" % (year, 10, (31 - (math.floor(year * 5 / 4) + 1) % 7)) # October
+    elif area == "eu":
+        start = "%d/%d/%d" % (year, 3, (31 - (math.floor(year * 5 / 4) + 4) % 7)) # March
+        stop =  "%d/%d/%d" % (year, 10, (31 - (math.floor(year * 5 / 4) + 1) % 7)) # Oct
+    return (start, stop)
+
 #------------------------------------------------------------------------
 #
 # HolidayTable
@@ -268,6 +306,7 @@ class _Holidays:
                                 "name" : "", 
                                 "offset": "", 
                                 "type": "", 
+                                "if": "",
                                 } # defaults
                         for attr in date.get_attributes():
                             data[attr] = date.get_attribute(attr)
@@ -312,6 +351,11 @@ class _Holidays:
                     # must be a dayname
                     offset = rule["offset"]
                 
+            if rule["value"].startswith('>'):
+                # eval exp -> year/num[/day[/month]]
+                y, m, d = date.year, date.month, date.day
+                rule["value"] = eval(rule["value"][1:])
+
             if self.debug: 
                 print "rule['value']:", rule["value"]
                 
@@ -374,5 +418,9 @@ class _Holidays:
                 print "ndate:", ndate, "date:", date
                 
             if ndate == date:
+                if rule["if"] != "":
+                    if not eval(rule["if"]):
+                        continue
                 retval.append(rule["name"])
+
         return retval