Miss out on the 24-hour Left 4 Dead Free Trial? No worries! Valve has announced that they're extending the trial until 5 pm GMT on Saturday. So if you don't already have the game client, just head over to this page and click "play it now" to start downloading. Then call up three of your friends and let the zombie-killing begin!
And don't forget, the game is on sale until May 4th. :D