This is some huge innovative shit I found a while ago. Basically how it works is that instead of playing a game on your local computer the game is played on a server somewhere and that server streams the video of the gameplay back to your computer.
This means that as long as you can watch a movie on your comp you can play any game availible without having to buy monster hardware for newest games. This works pretty good too, its moderate delay if you are far away from the servers (UK/USA) but still very playable.
Check this out geekens, you can party any game they have for 30 minutes, completely free:
http://www.onlive.com/
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