Before the discovery of the balloon, it was thought that the only essentials for a party were friendly guests and a CD of whale screams. Get ready for a modern get-together with today's Groupon: for $90, you get a four-hour sumo-wrestling party with referee from Sumo Mania (a $180 value).

Founded with the goal of sprucing up spiritless special events, Sumo Mania bumps soirées into the stratosphere with all the supplies needed for four hours of simulated sumo excitement. Foam-filled sumo outfits ensconce would-be rikishi, or wrestlers, in a layer of protective padding imitative of the sport’s most physically adept athletes. Once suited up and prepared for battle, wrestlers are let loose upon an extra-thick padded mat to settle lifelong grudges and decide who gets first dibs on the buffet line. To maintain a fair match, one of Sumo Mania’s qualified and whistle-equipped referees will be on hand as an impartial arbiter of any disputes over rules, victory conditions, or universal systems of morality.