Would you consider it a turn off if you find out your date was on a TV show like Are You Smarter Than a Fifth Grader?

yes, if he lost.

seriously, though, why?

If he won, it would be okay. If he lost, it would be a turn off, but I wouldn't turn someone down for another date because of this and no other reason.

Not a turn-off either way (winning or losing - I completely understand how someone could freeze and lose even though they're smart in real life.)

Is she fat???