"Collabolla" (aka collabowobble) is a videogame where you have to sit astride an inflatable ball (like the '70s "Spacehopper" balls), bounce, rock back and forth, roll or jump around to send commands to the computer.
The two players don't play against each other but have to join forces and co-ordinate with each other to control the same character's movement and combat a common enemy.
The joystick is replaced by the balls: one for the x axis and one for the y axis, one moving pacman up and down, and the other left and right.
This is only a prototype, by Jennifer L. Bove, Simone Pia and Nathan Waterhouse, but I'll cherish the one who would manufacture and sell it.