After feeling the heartbreak of seeing MMOAsteroids last week turn out to be an April Fools' joke, I decided to take things into my own hands. This afternoon hack project I threw together yesterday using Firebase.
I adapted a simple single-player asteroids game off github (https://github.com/dmcinnes/HTML5-Asteroids) and made it fully multi-player with Firebase.
It's set up to spread out users across a bunch of games to avoid having 500 HN'ers on the same page. Login with Twitter so other people see your picture...