Valve Limit R at Insert Coin '09.
I've played some shitty games in the past but this one really takes the piss. Quite easily the worst racing game I've ever played, on console or in the arcades. It has the quite bizarre inclusion of giant polygonal transsexuals who pop up and cover a third of the screen whenever you crash or make a jump etc... Makes for quite a hilarious experience, and takes your mind off the force feedback wheel which is tearing your arms out of their sockets.
I'm not sure which arcade operator decided to bring this to the show, but they had quite optimistically put a 'for sale' sign on it. I don't think they will have gotten many phone calls from interested parties.