Dosbox is an MS-DOS emulator that allows you to play old DOS games on new computers. It is free software licensed under the GNU General Public License and works on Linux, Mac OS and Windows. There are tons of great games that will make you feel nostalgic. Some of the most popular games are Doom, Warcraft, Mortal Kombat, Worms, Cannon Fodder, Winter challenge and many others. To download dos box go to their site at Dosbox.com.