Dad: So did you give blood on Saturday?
Dad: Good for you. Hey, what blood type are you?
Me: Um, O positive.
Dad: huh, you've got your mother's blood type. Your brother has mine, A positive.
Me: Ha! You're on the roof! I'm not on the roof, but you're on the roof. *does geeky little dance*
Of course, when I conveyed my father's blood type to another coworker (a recent fan due to your's truly) he said, "ha! He's on the roof." I am such a geek, but at least I've got company.