Regarding C&C: Oh yeah?? Guess you missed these little memo's on Red Alert and Command and Conquer, dude.
I think they're even OPEN SOURCE these days...
Red Alert Freeware
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http://compactiongames.about.com/od/...htm?once=true&
Command and Conquer Freeware
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http://www.shacknews.com/onearticle.x/48749
Really? You didn't know about this?
For shame that Quake 1-3 isn't freeware tho... even if the game-engines are Open Source.