Menusigne
Menusigne is a "serious game" for learning sign language grammar. The initial version presents a short course in Langue des Signes Française (LSF; French sign language), which will teach you 125 signs and grammar for finger-spelling, numbers, basic declarative sentences, questions and negation.
The game has three levels. Start at the practice level, where you choose signs from the menus in a line, then press the arrow key at the end of the line to create an avatar-based animation.
At the play levels, press the Play! button to get an animation or a live video, then use the menus to choose the correct meaning. You score points for a correct answer, lose a life for an incorrect answer. More points are awarded at the video level.
You can find full instructions here (English) and here (French)