Since I talked about the Easter name earlier today,
I though I would give the standard answer on how they pick the date
for Easter, i.e. the first Sunday after the first full moon after
the vernal equinox.

I look it up an discovered I was not quite correct. The U.S. Naval
Observatory offers a more interesting and arcane answer!

Here is the introduction to their answer!

The commonly stated rule, that Easter Day is the first Sunday after
the Full Moon that occurs next after the vernal equinox, is somewhat
misleading because it is not a precise statement of the actual
ecclesiastical rules. In order that the date should be
incontrovertibly fixed, and determinable indefinitely in advance,
the Church constructed tables to be used permanently for calculating
the age of the Moon. Easter is determined by the "ecclesiastical
moon" defined by these tables, which is not strictly identical with
the real Moon. In addition, the vernal equinox (the time at which the
apparent longitude of the Sun is zero degrees) is fixed at March 21,
not by the actual motion of the Sun. Moreover, the date of Easter is
determined independently of any meridian of longitude, and is always
the same in all time zones, unlike astronomical phenomena.

--- If this has not brought “tears to your eyes” you can get the
full details by clicking on the Naval Observatory site below ! ---

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Source: http://aa.usno.navy.mil/AA/faq/docs/easter.html
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You should note that this is the Western Easter. The Eastern Churches
have a different interpretation and thus a different date. Many
erroneously think it is due to the difference between the Gregorian
and Julian Calendars. This is not the case since both Easters are
derived from astronomical phenomena regardless of how the calendars
differ. For example, certain Eastern churches use the same formula but
then insist that it is the next Sunday after Passover has ended.
As a result most years have the Eastern Church Easter a week later
than the Easter in the Western Church. About once every 7 years they
line up as it did on April 15, 2001 . You can also have a very wide gap, as in 2002, when the Western Church had it on March 31 and the Eastern Church had it on May 5. This happens about once every 11 years.