Operation Flashpoint, did you played it? Good. Its real successor is the ArmA series.

Well ArmA 3 was announced months ago, but now it's the first time Bohemia releases a public demonstration, in 8 videos:

http://www.pcgamer.com/2011/09/13/arma-3-website-goes-live-with-gamescom-presentation-videos/

And, for future reference:
http://www.arma3.com/
http://www.youtube.com/user/Arma3official