Miniclip

MINICLIP.COM boasts more than 300 games -- from puzzles to shoot 'em ups
to multiplayer challenges -- that will keep kids zoned for hours on
end. Most of the games can be played within a browser, though some need
to be downloaded. Visitors can register and create a "mini-me" avatar
and profile, then challenge their friends to games or send them
preselected messages. There's a lot of (juvenile) political humor on
the site, like an Obama vs. Hillary streetfight game -- choose your
candidate and taunt, kick, and slap your way to victory.

The focus on fighting and war gets a bit old, but there are plenty of creative games on the site -- like the awesome adventure game Cheese Dreams, in which you are a cheese moon running away from hungry space mice. Some of the super-simple games are the most addictive -- try tearing yourself away from Ping Pong, which involves nothing more than bouncing a ping-pong ball on a paddle over and over. The players section adds a fun, social element that kids have almost come to expect from websites these days.

Online interaction: Players can register for an account and challenge their friends.