Left 4 Dead 2

Everyone has Green Flu Fever, or Green Fever Flu. Something like that. And it's a hard time in the big easy for 4 charismatic goofballs, shootin' and slashin' their way through a horde of zombies and equally charismatic "Special Infected." This incredibly generous game encapsulates the first entry in the series, and proves an excellent example of Valve at their finest, both in terms of design and after launch support. It's the rare competitive game that can get two beta boix like us to sit up and take notice, and it remains extremely playable more than a decade after release.