The search for a sole peanut in a cardboard box filled with packing peanuts. Upon finding the normal peanut you ship it back to the sender and he will ship back a prize. Prizes can be anything the original sender desires to mail. In most cases it is chocolate coins, colored pencils, or miscellaneous office supplies.
Dude, don't dump those package peanuts! Dupp that!
You guys I'm telling you, I totally Dupped it! I'm gonna mail it back!
As a result of the Duppage, I got a stapler.