Open games by popularity
The term open is used for games when most parts of the source code are publicly available. Many of these games are published under the GNU General Public License (GPL) but also a wide variety of different licenses are used as well, some are more popular than others and some are custom ones. A game can have more then one license, one for the engine and another one for artwork or music. A game who's artwork is not published under an open source license is still eligible for this tag if the game code is.
VICE is an emulator of Commodore's 8-bit computers, so you'll be able to run programs written for Commodore 64, C128, VIC20 and some other systems under Linux, Windows and other...