I've been playing Haxball since it was originally posted on teamliquid back in December 2010, and since June managing a draft league for it for players in the pacific region.
It's really cool because the game is really easy to pick up and learn but there is still a lot of room for individual brilliance and creativity. Not only that, but there are different leagues all over the world to play in: I know ESL runs a league for it (for 1v1, 2v2, and 3v3), I know there's a French league, there's a AUS/NZ league, there's a league for the eastern side of the US and Canada, there's a league in Mexico, there's a league in Hong Kong, and I'm sure there are a bunch of others that I don't even know about.
Right now (on a Sunday evening) there is almost 2000 players playing, which is pretty cool (and I think a pretty slow day) for this neat little flash game.
We've just completed the 4th season of the Pacific league (the one I run) and are about to start the playoffs on Monday (with the grand finals being on March 7) so now and next week would be a great chance to tune in and check out the game being played at a pretty high level. Otherwise you can always just jump in and play the game (I'm 1124 on the west coast rooms if you want to say hi!).
Here's some highlight videos from the beginning of the season if you want to see the kinds of stuff you might see in a live game:
+ Show Spoiler +
week 1:
week2:
week3:
week5:
Please come play the game, it's a lot of fun & it's always great to see new faces!
If you want to see our old game footage (or tune in Live@8PM Monday-Wednesday): www.livestream.com/pachax
If you check out the community links on the Haxball homepage you should be able to find some of the communities & leagues around the world if you want to join.