As Nick highlighted in a news post the other day, Steam is currently running their annual holiday sale from now until January 3rd and this means a lot of great co-op title can be snatched up (or gifted, in the true holiday fashion) at a great price. Well for the next 24 hours only, you can pick up Serious Sam HD: The First Encounter at the low, low price of just $9.99, and Left 4 Dead 2 for just $33.49. Picking up both titles rings in at $43.48, the price you'd likely pay, with sales tax, for Left 4 Dead 2 just by itself. That's a lot of co-op possibilities for that price, and Serious Sam HD: The First Encounter by itself could make for an excellent last minute e-stocking stuffer!
Source: Store.steampowered.com