Genre: Action/Arcade

Players: 1 - however many you can fit around your keyboard

A massively-local-multiplayer space marble sumo game. Press Escape to quit, or any other key to join the game. Hold your key to charge up and release to jump. Be the last marble standing. Or rolling, or whatever.

(The game should support most/all keyboard keys. If you decide to do something foolish like playing as Alt and F4, that's not my problem.)