A Left 4 Dead 1 contest last year where people were challenged to take funny, unique, inventive pictures in front of a L4D ad was met with a huge response. Because of this, there is a new contest this year: “The Dude Where’s my Thumb?” photo contest, ending November 15th.

The contest is simple: take a funny, interesting, scary or otherwise unique photograph of you or a friend in front of one of L4D2’s outdoor media placements (billboards, bus ads, etc.) Valve president and founder Gabe Newell will then select the best photo to win an ‘Infected’, hand-painted, laser engraved and custom designed, Xbox 360. Twenty-five runners-up will receive Xbox 360 copies of Left 4 Dead 2 autographed by the L4D2 team.

Get those creative juices flowing and go hunt down a L4D2 ad with your camera!

http://www.l4d.com/contest/ for full details.