There is this small simple multiplayer browser game which I am playing from time to time during a break or when waiting for a build to finish: Airmash
. It looks like this:
I noticed that a surprising amount of the players on there are developers, too. I can also recommend this game for resetting your brain again when facing a problem, works surprisingly well.
I'm not sure what the business model of this is, though.
Ill try the game another time, hopefully catch some players. Albeit Ill be at a big disadvantage, given the server-sided physics and my Australian ping :P