JFrog is a free distributed components-oriented framework created to develop multiplatform game engines with high source code reusability. Its possible to create game engines for personal computers and handhelds. Before this project was Amphibian.
Lixoo is a extensible, fast and small 2D point'n'click adventure game engine. It features the engine itself and an IDE that let you create full-featured games just by writing the essential code of the game.