I'll confess to not remembering seeing a Fold-In from Mad magazine when I was a kid. I'm sure I saw them on the occasions that I could get my hands on one. This was a rare occurrence as the magazine was frowned upon by my folks. Regardless, the N.Y. Times has an article up on Al Jaffee. The guy who makes the Fold-Ins. The article is interesting by itself, but make sure to check out the gallery of Fold-Ins. These things are amazing.