Pyramid Shambo is tournament-style Rock Paper Scissors (aka Roshambo), with pyramids used as scoring chips. Pyramid Shambo is to RPS what a Texas Hold ‘em Tournament is to a single hand of classic poker.
Each player in turn challenges another to a round of Roshambo, with the loser paying the winner a small pyramid, making change as necessary based on pip counts. Every time there's a tie, the payout escalates and the players continue to throw until there's a winner. A player gets a bonus for eliminating another, and the eliminated player's pyramids are removed from the game. The last player standing wins.
This was made available on the Looney Labs web site late in 2011 as the company's holiday gift to fans, presumably as a revision of the 2009 gift Nothing Beats a Large.
Also included in Pyramid Arcade.