Cracked
Originally starting as a magazine specialising in satire for American students, Cracked has evolved to become one of the most annoyingly addictive websites on the net. 100% of the articles are completely pointless, (eg The Lunatic's Guide to Hacking Into Anyone's Voicemail) but they are quite funny. You'll stumble across one article, enjoy it, read another, then another - until 12 days later you'll find that you're lying in a pool of your own waste having not moved from that spot. Ok, that might be a little bit over the top, but it is an addictive website.