HaxBall is a realtime multiplayer game that plays like a mix between football and air-hockey, and it's a real blast.
Player skill makes a big difference and teamwork shines when playing in teams of 3v3 and 4v4.
HaxBall is programmed with the Haxe programming language.
HaxBall uses WebRTC to create peer to peer connections between the players and the room host. This technology is still fairly new and, unfortunately, some browsers (most notably Edge and Safari) don't fully support it yet.
First released in December 2010, HaxBall was originally implemented using the flash player and used RTMFP to create peer 2 peer connections in a way similar to WebRTC.
Unfortunately flash player has been discontinued and so the move to HTML5 was required.
HaxBall is made by Mario Carbajal (aka basro).
Special thanks to my brother, gliptic, qualo and jonsul for their miscellaneous help.
IRC: #haxball @ irc.freenode.org