DOSBox

DOSBox rules. In particular, it's been letting me play Scorched Earth on my WinXP and Linux boxes. DOSBox's video operations can be a bit slow, which becomes fairly evident after a large explosion goes off, but the game's very much playable. Setup is a snap too. It takes a minor amount of DOS knowledge to work one's way around, but very little at that.

DOSBox is able to run Second Reality as well, a demo that continues to amaze me, especially considering that it ran at full framerate on a low end 486.