http://www.kiekko.tk is an internet icehockey game using java. Really interesting and worth trying
http://www.netsoccer.biz same format as kiekko.tk but it's football and it's runned on users computers so you don't need java.
http://www.urbandead.com "is a free-to-play browser-based multi-player game where you play the survivor or victim of a zombie outbreak in a quarantined city centre, alongside tens of thousands of others."
Those are what I've been playing for now and what I've found on internet. Reply here if you know more that kind of games.


