NetRisk GWT allows anyone to play a full game of Risk with up to 8 players from any Javascript enabled browser. Bases on the code of NetRisk 2.0 (https://sourceforge.net/projects/netrisk/) Demo: http://www.netrisk-online.de/
Freeciv-Forever.com is a Free and Open Source strategy game which can be played online in a browser against other players, or in single player mode against AI opponents. There is a playable live demo at www.freeciv-forever.com