Do you know Quake Live?
It is one of the best deathmatch games ever created is now available to play from within the confines of your browser.
Quake Live uses a plug-in and then goes full-screen when you play - but the spirit is still there.
Any modern computer is now able to handle Quake's modest demands, and the game's blisteringly fast action makes it quite unlike any modern shooter. Forget realism. Forget objectives. Sometimes, all you need is a rocket launcher, a perfectly timed shot and the lamentation of the noobs as time permits.