Easter Calculations...Huh?

Yesterday I came to the realization that Easter is this coming Sunday, March 23rd. Now, I'm not particularly religious--I honestly can't remember the last time I attended a non-Christmas Church service--so I guess I could use that as my excuse for Easter sneaking up on me. When someone reminded me about the upcoming holiday, I was stumped when I tried to figure out how the date for Easter is calculated.

Wikipedia to the rescue:

The rule has since the Middle Ages been phrased as Easter is observed on the Sunday after the first full moon on or after the day of the vernal equinox. However, this does not reflect the actual ecclesiastical rules precisely. One reason for this is that the full moon involved (called the Paschal full moon) is not an astronomical full moon, but an ecclesiastical moon. Another difference is that the astronomical vernal equinox is a natural astronomical phenomenon, while the ecclesiastical vernal equinox is a fixed March 21. Easter is determined from tables which determine Easter based on the ecclesiastical rules described above, which approximate the astronomical full moon.

That makes sense, sort of. I found this passage even more interesting:

The calculations for the date of Easter are somewhat complicated. In the Western Church, Easter has not fallen on the earliest of the 35 possible dates, March 22, since 1818, and will not do so again until 2285. It will, however, fall on March 23 in 2008, but will not do so again until 2160. Easter last fell on the latest possible date, April 25, in 1943 and will next fall on that date in 2038. However, it will fall on April 24, just one day before this latest possible date, in 2011.

The cycle of Easter dates repeats after exactly 5,700,000 years, with April 19 being the most common date, happening 220,400 times, or 3.9% compared to a mean for all dates of 162,857 times, or 2.9%.

I vaguely remember my high school biology teacher explaining the above rules to my class one afternoon, but of course I wasn't paying attention. Hey, it was high school biology, no one pays attention!