Head over to greenmangaming.com and you can get a free copy of Earth 2160, haven't played it myself but apparently it's a 3D RTS released in 2005. The "sale" should be up for a little over twenty more hours as of time of writing.
http://www.greenmangaming.com/s/us/en/pc/games/strategy/earth-2160/
Edit: Also apparently only one copy is available per IP address. Dunno if you can use a proxy to get multiples though.
http://www.greenmangaming.com/s/us/en/pc/games/strategy/earth-2160/
Edit: Also apparently only one copy is available per IP address. Dunno if you can use a proxy to get multiples though.