* I played Kingdom of Loathing back when it was a bloated Visual Basic/ASP mess circa 2003. Since then, they switched to PHP, started a neat online radio station, and a wiki: I'm playing again as of a week ago.
* What if the world looked like this? Play eRepublik to help shape it: I virtually live in eFlorida, which happens to be the capital of eUSA after a protracted war with members of the PEACE alliance that nearly broke the nation; that alliance has since weakened and new ones forged.
* Urban Dead: I've already "beaten" as in reaching level 41/42 without becoming a semi-revivable zombie. However, you can play different human classes, or stay a zombie, or treat fellow humans or zombies like crap if you want.
* If you're not worried about playing with others, time-wasters galore can be found on Newgrounds or Adult Swim.