DOSBox
DOSBox is a free application that emulates DOS running on an x86 PC, allowing old DOS games like Eamon-PC to be run on most modern systems including Windows, Mac, and Linux machines. It was developed by Peter "Qbix" Veenstra, Sjoerd "Harekiet" van der Berg, Tommy "fanskapet" Frössman, and Ulf "Finster" Wohlers, and first released on 22 July 2002.
Some applications add graphical environments or other extended functionality to the base DOSBox emulator; one popular example is D-Fend Reloaded.
In the browser
Js-dos is a Javascript version of DOSBox created by Aleksander Guryanov (@caiiiycuk) that can run DOS programs and games in a web browser. Author and developer Derek Jeter uses js-dos to make his Eamon Deluxe-based adventure The Treachery of Zorag playable online.