Deacon say potato is a running gag in Video Games Awesome that first occured in the Earthbound FanFest live show. Many members of The Chatroom requested Deacon to say "potato" throughout the show. At some point during the show, Fraser took notice and began to threaten to ban anyone who asked Deacon to say potato, not being in on the joke. (Editor's Note: what joke??)
On the Anniversary of Awesome Video Games episode, the live chat once again asked for Deacon to say "potato," which he finally did, although in a completely puzzled tone.
If you quote this in the chatroom during a show, it will likely result in a timeout.