With Easter coming up this Sunday, it seems like a good time to mention this web page: Holidays On the Net. This site has dates and lots of fun information about all the different holidays throughout the year. But the feature I like best is it's Easter Calculator. You plug in the year, and it responds with the date that Easter fell on that year.
This is handy when trying to figure out the date of old photos, or references to Easter in newspaper clippings, church newsletters, etc. I was given a snapshot of my husband as a child, lined up with his sisters on what was obviously Easter morning -- they were decked out in the Easter finest. The photo developing company had stamped 1965 on the bottom of the print...but the Easter calculator gave me the actual date: April 18, 1965.
As I mentioned before, they have fun information and activities for holidays all throughout the year -- so browse for a while, and enjoy. I hope the Easter calculator is as useful for you as it was for me!