A nice browser game. It this case you are a commander of a culture developing in a post nuclear war wasteland. You build mechs - huge, customizable walking robots to fight for the control of the planet...more or less...
Anyway, the game is very exciting and addictive
good news you don't need much time to play.
I played the alpha helping my my buddy test it and it seems soon there will be an open beta:
http://beta.mechhero.com
Go enjoy it!