The new Computer Science AP case study--GridWorld.
GridWorld has a graphical interface so that students can see, test, and prove the fruit of their labor. The graphical nature of the projects engages and motivates because of its "game-like" appeal.
Students are typically very highly motivated with this particular case study... makes debugging code easier and fun.
Be sure to check out the free chapter download and the associated
(New! Blue Pelican Graphical Labs... manual & DVD... it's not what you might think!... find out more)