On most days, search engines, social-networking and technology Web sites soberly strive to provide informative content. But on April 1, they get a chance to poke fun at themselves and the readers they serve.

Google is well-known for its April Fools' pranks. In past years, the search portal offered bogus products such as Google Romance and Google Gulp. This year’s fake sites include Google TiSP (a free in-home wireless network operating through sewage lines) and Gmail Paper, which claims to offer paper archival for users of Google's e-mail service.

Another annual online gag is fake products offered on the ThinkGeek Web site designed to cater to popular hobbies amongst tech aficionados. This year’s selection includes an attachment offered for the Nintendo Wii, inhaled caffeine sticks, a digital photo frame showing pictures of a virtual vacation, and an advertisement claiming the upcoming Apple iPhone is now shipping.

Dozens of Web sites offer fake press releases of fictitious news, such as Dungeons & Dragons producer Wizards of the Coast announcing a licensing partnership with parent company Hasbro to release a D&D-themed Monopoly game titled "Monopoly: There and Then"; Facebook’s "Introducing LivePoke," where the site would dispatch a person to poke a friend of the user’s choice; Slashdot’s introduction of a Slashdottit rating system, and Microsoft’s release of a new online service for Xbox Live called "HomeLESS."

Other popular sites show radically redesigned front pages or bogus content, such as a fake picture of space’s first Quidditch match on NASA’s Astronomy Picture of the Day; a CNETNews.com front page that shows Microsoft founder Bill Gates as being logged in, and PC Magazine’s “10 Revolutionary Technologies” that include a Wii helmet and a toothbrush with built-in wireless internet.

Want more? Aprilfools.urgo.org has a list of sites that have April Fools' jokes this year. Also, a long list of gags is available through Wikipedia.