Nick Trost's Classic Packet Tricks - Horsin' Around

Three cards are shown, each with a part of a cute, topless pin-up girl—there's
her head, her middle, and her bottom! The head and middle are dealt face down
on the table, and the bottom is inserted back out partway into your pocket.
You now ask someone where the middle is. They say, “On the table . . .”
But you remove the card from your pocket and show it is now the middle! The
middle is placed between the two cards on the table. The big surprise comes
when you now offer to reveal the complete picture. The cards are turned up and—instead
of the girl—there’s now a picture of a shabby horse . . . you've
just been Horsin' Around! A great bar and party gag. Good for a laugh every
time. Real easy to do.