In a questionable act of legal responsibility, Archive.Org has posted over 2,300 MS-DOS video games to their website. Just by clicking their website you can download the available ROM for your own offline emulation use or simply play the game in your browser via the DosBox embedded emulator.
The wealth of content here is immense and it will be interesting to see how long some of these titles will still be available, as some are still being sold online.
Some Stand out titles include..
Bust A Move
Prince of Persia
Indian Jones And The Last Crusade
and tons of other awesome shit
The web link can be found here: https://archive.org/details/softwarelibrary_msdos_games/v2