I have been messing around with a new rts lately.  It is significantly different in visuals to any past rts that I have played but interesting nonetheless.  It is simple, clean, and challenging.  Available for both windows and linux.

Developers description of the game:

Dyson is an ambient real-time strategy game with abstract visuals.

Remotely command semi-autonomous self-replicating mining machines to take over an entire asteroid belt.

http://www.dyson-game.com/