Valve is putting Left 4 Dead on sale for 50% off this weekend:

This Friday the 13th brings us a little closer to the zombie apocalypse. Whether or not you’re superstitious, Left 4 Dead is 50% off this weekend only. So grab a shotgun and make a run for the next safe room.

It’s the zombie apocalypse. Bring friends.

If you’re reading this blog, I suppose you already have a copy… Hmm, maybe you have friends who would be able to take advantage of this?