Most DOS games that are no longer being supported by their parent companies eventually fall under the catagory of Abandonware. Abandonia is a great site for Abandonware (I personally recommend Strife, it was the final game using Doom's engine, it works best with ZDooM.)
For the card gamers out there. There's Apprentice, for Magic: The Gathering, and Yugoh Virtual Desktop for YGO players. I've also found a very well make online battle program for Pokemon enthusiasts: Pokemon Netbattle. What else...
At swirve.com we have Utopia and Earth:2025. Utopia is a more team oriented turn based strategy game, while Earth can be played alone. They both have sort of the same premise. Build Army, Go to war, become most powerful nation. When you learn how to play and start getting into it, both games have a great deal of depth in strategic possibilities. And they become very fun to play.
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