The Top 100 April Fool's Day Hoaxes of All Time:An illustrated list, by Alex Boese.
All-4-Free Freebie Tree: Provides pranks, jokes, and downloadable freebies.
April Fool's Day Prank Software: Offers free harmless joke and prank software.
April Fools on the Net: An archive of net humor, pranks, jokes and foolishness.
April Fools Practical Jokes Gag Gifts: Contains a list of pranks from 1990 to present day. Also includes ideas for gag pranks.
April Fools' Special: History's Hoaxes: National Geographic compilation that includes explanation of how some hoaxes were done, how they were spread, and eventually debunked. Includes definition and history.
Microsoft Buys the Open Directory -- or Not: Information about 2002 "acquisition" of the ODP by Microsoft. Includes a screen shot of what the main web page looked like.
The Kremvax Hoax: Describes story of how the USSR joined the Internet in 1984. Include original usenet posting and followup. Maintained by the perpetrator himself.