It's reasons like this Valve remain one of my favourite developers - they do things because they know it will generate some laughs. It's not all about the realism, you know. So take a look at the Easter Egg found in the Left 4 Dead 2 demo. It's found on a Jukebox in a cafe' just after you climb onto a truck. I'll leave the surprise intact - but if you didn't get the reference, shame on you. [yo... more.