Deliantra is an advancement of the crossfire multi-user RPG game. Unlike the original project, it focuses mainly on stability and playability, but also adds modern technology such as map scripting, Perl server extensions, asynchronous I/O, higher resolution graphics, and better client support.
Sauerbraten (a.k.a. Cube 2) is a free multiplayer/single player first person shooter, built as a major redesign of the Cube FPS. Much like the original Cube, the aim of this game is not necessarily to produce the most features and eye candy possible, but rather to allow map/geometry editing to be done dynamically in-game, to create fun gameplay and an elegant engine.