Perhaps you’re a fan of Professor Falken in Wargames, or you miss playing Global Thermonuclear War over AppleTalk with GameMaster. Defcon from Ambrosia Software is like that, but updated with modern graphic, soundtrack and network play.
Unfortunately real nuclear war is probably a lot faster.
That’s been out for a year or so, and it’s actually produced by Introversion, the same people who did Uplink and Darwinia.
… oh wait. Macintosh.