A mod for Battlefield 1942, see bf40k. The game involves you running around as a Warhammer 40K infantry and entering classic Warhammer 40K vehicles from each team.
Guy 1: Hey, have you seen Battlefield 40k?
Guy 2: Hell Yeah, I'm an alpha tester
Guy 1: You lucky bastard, I only registered on their forums, which I found linked from www.Battlefield40K.com