Have you been abstaining from zombie slaying until the cost of entry dropped to the low-low price of free? If so, you're in luck. Valve is making Left 4 Dead
available to all Steam users for free
this "Freaky Free Friday" with a 24-hour trial version available at 12:01AM GMT. However, you can download and preload the game and the free Survival Pack DLC right now to get ready for a day with the undead.
We suggest calling in sick to work, ditching school and skipping Aunt Mabel's funeral (she might be a zombie herself, after all) if you haven't been a part of this game yet. Just don't blame us when you yearn for more undead cleansing the next day and end up (*gulp*) spending money!