Will Ferrell showed up on Letterman Tuesday night dressed up as a very large version of something that normally is very little- a Leprechaun to promote his new movie. And then last night he went on Jimmy Fallon and even though it wasn't a snack cake holiday, he dressed up as Little Debbie, of snack cakes fame. We don't know where you would actually go to get a Little Debbie costume, or whether there was a product placement deal here, but Ferrell was committed to the role and totally aced the closed-eyes-snack-cake-challenge.