Real time strategies
Single player missions are on the planet Carver 5, where various clans are fighting for control over the planet. You, as a mercenary, will provide its services to those who offer more coins.
The story is presented with short movies between the missions. Also, there are big movies between the campaigns. And the moves are quite interesting. ;)
The graphics and the 3D game engine are very impressive. (Just don't forget to set everything related to graphics to the max - it can make a big difference)
Now the best news is - the game is on this site, because it is free :) In 2006, Microsoft released a modified version of the code of the game, along with the assets necessary to build the game. In other words - they've released a free version.
Unzip the archive, then unzip the archive that is in it. You will get an iso file that you can save on CD, or mount as virtual CD, or extract. Then run setup.exe. If you select FULL installation, you will no more need the iso file (or the CD if you burned one). Good luck and enjoy the game!
http://www.shacknews.com/file/20899/mechcommander-2-free-game
Official site (no longer available):
http://mechcommander.org/
http://www.microsoft.com/games/mechcommander2/
Game trailer:
Game video: