I love this site, it's got a bunch of online games. Sherwood is my favorite, slaying dragons is great for stress. Followed by Tank ball, you get to drive around in your own little tank and blow the shit out of the other players driving around. Both the games are multi player.

You also have things like Marian's world, the dance club game, ratinator, and a couple others. As far as 3d games you don't have to download go those are pretty fun.