0 A.D.

[B0rsuk]

http://www.wildfiregames.com/0ad/

Really promising game (under heavy development). Probably the most promising community game project I've seen, certainly the most promising RTS project.
Check out the website, you'll be amazed. Graphics is disturbingly good (screenshots, concept art... not so much great technology as great style). It's meant to be heavily based on history, except for areas where it would harm gameplay.
Oh, it will be free, possibly even opensource. The authors promise lots of modding potential.

Six nations: Hellenes, Romans, Iberians, Persians, Carthaginians, Celts.

[NTJedi]

This RTS... will it have a setting to adjust the game speed on the fly as seen in the original Stronghold and Stronghold:Crusaders ??

[Yucky]

I would love to have the ability to change the speed of Real Time.

[DominionsFan]

Yeah the game is really promising. Thanks for the link Borsuk!

[Endoperez]

The game is just as promising and almost as incomplete as when I found about it. If they can pull it off, it will be awesome. I'm hoping they manage, but I won't hold my breath.