Mac: Computer games have come a long way since the days of Doom, Zork, Tie Fighter and Castle Wolfenstein, but many of us who grew up with those games would like to replay them. Boxer is a free app that will let you play any DOS game on your Mac.
After installing the app you can download any DOS game and import it into the app by dragging it into the import window in Boxer. You'll never see a terminal window.
Options include using a joystick, locking your mouse pointer so it can't accidentally mess up your game, and rendering the graphics four different ways: original, fast smoothing (MAME), Fancy Smoothing (HQx), and with added TV scanlines. You can also switch from full-screen to the 4:3 aspect ratio that PC monitors at that time used.
If you're a retro gamer or just want to try out some of the games you parents keep talking about you may want to give Boxer a spin. Note that there are two different versions of the app -- one is for Mac OS X 10.5 and up and the other is for 10.4 and below. The app comes with Commander Keen 4 and demos of Epic Pinball, Ultima Underworld and X-COM: UFO defence.