By which I mean amusing things that happen in real life that are related to games rather than funny things that happen in games.
I'd picked up Ratchet and Clank: Going Commando and loved it, so I went to Gamestop during a buy 2 get 1 sale to find the other three games in the series. Found them all so I went up to the counter to buy them. It was a slow day so there were two employees at the counter, a guy and a girl. The guy looks at the games I'm getting and says, "Looks like you're just missing Going Commando." The girl says, "Oh, I love Going Commando!" We both look at her trying not to laugh while she realizes what she just said and turns a nice shade of red