www.freerice.com It builds your vocab, and you get to help people. Randomly searching Wikipedia for stuff is fun too.
Read Digg and Gizmodo/Engadget is what I do. Avoid sites like Newegg, if ur a techie, cause that leads to buying unnecessary stuff. I do it a lot :*(
i used to get on everyday 24/7 doing....pretty much useless things like gaming and stuff. now its just homework some gaming news facebook
Make Graphics... its the best thing... listen to music playlist.com or Youtube.com... Avenged Seven Fold.. Little Piece of heaven Wierdest and most f*cked up song ever but pretty cool and make some signatures.. with adobe photoshop.