Have you ever played the old bar game, "Bullsh!t"? Mash PotatoS essentially is exactly that, but with potatoes instead of numbers. A group of players sit around in a table with the deck in the middle. When it comes to their turn they draw a card and place it in the "bowl" claiming out loud what color the potato is. It then goes onto the next turn if no one yells "Mash!" accusing the played card's claim a lie. If the accuser is right he would win; if not he would lose his next turn. No matter what color the potato actually is, the same color can not be claimed twice in a row.