Two players, one keyboard. Sit next to each other.
BLUE taps A. RED taps L. Every tap is a shove. Shove the other one off the edge.
Holding the key down does nothing — it has to be real taps, or the keyboard would play it for you.
The floor creeps in from both sides the longer a round lasts, so nobody can just stand there.
A big clash throws you both apart, which gives you room for a proper run-up. First to 3 rounds wins. R to start over.