The Washington Post has attempted to comprehensively list all April Fools pranks and hoaxes appearing on the internet today, helpfully separated into categories. There's still April Fools Day on the Web (mentioned twice, previously) which has a collection of jokes, spoofs and parodies around the internet, with annual records going back to 2004. For older records, there's a far from complete Wikipedia list of April Fools' Day Jokes, with a slim selection of notable hoaxes going back to the 1950s, while the Wikipedia article on April Fools' Day goes back much further. Snopes breaks down the legends behind the term (previosuly).
On Sunday, April 1, ThinkGeek.com jokingly introduced the 8-bit Tie, and due to customer demand, claims that now it'll be a real product. On Friday, April 13, apparently due to customer demand, hard drive manufacturer WiebeTech has now introduced the MouseJiggler, and claims it's not a joke.
Must-haves for your coffee table, lavatory reading, or just killing time on the subway: The Nutritional Benefits of Nose Picking; Perfecting the Art of Fart Projection (NEVER be blamed again!); How to Murder a Complete Stranger (and get away with it) [paging scarabic]. These and other eyebrow-raising books can be yours, assuming you already have a book that you can put these dustjackets on. FlapArt: The Alternative Book Cover.
Letters to a new employee I think it's so nice that the President and CEO of Starbucks International would send a welcome letter[s] to such an unimportant person. Don't you?
RoboDump I need one of these for my workplace
Finally, an Internet "really short quiz with astonishing results" that is 100% accurate.