Some of the fun and free computer games include Extreme Racers, The Lost Kingdom Prophecy, Battlefield Heroes and Three Musketeers Secrets. There are lots of free computer games that you can get online. Check out http://www.gametop.com/ and http://www.games.com/ for some of the available games.
umm if you have a steam acc team fortress two is free and its fun i havent played it myself but it looks like a lot of fun...or are you talking about flash games? cause pacman is a good way to kill time :D