I'm usually a fan of open source games but rarely do they manage to be actually great. People like giving recommendations like Super Tux Kart that haven't aged well and don't play well. What are some open source games that are legitimately good that I've missed?
OpenTTD: Old transport tycoon game, but really fun especially in multiplayer
Minetest: Minecraft-like voxel game engine, which means there a many different game modes
Beyond All Reason: Great RTS, also great in online multiplayer or with some friends. (Disclaimer: Possible unfree licenses for artwork)
Dwarf Fortress (free but not open source, thanks for telling me that one): not everyone’s cup of tea, but sometimes you just get stuck in it for hours on end
Dwarf Fortress is not open source. It is freeware. Parts of the game (some graphics stuff) has the code available but you have no license to distribute it.