http://www.spread.org/ waht do you think? Wouldn''t this be very suitable for games?

Looks interesting. Not sure what the overhead would be for games though, as there looks to be a lot of features which would be unnecessary for JoeHackers MMORPG o'' Doom, looks more like what corporate collaboration systems would be built on.. possibly. I have to admit I haven''t done much more than skim the docs, somebody will no doubt prove me wrong

WarDome: PHP MMORTS In Development