The golf applet is up and running. Kids got a kick out of it and are now designing their own applets. We've done our work with developing trig ratios, solved a few problems involving right triangle trig and have previously worked with the fact that vx and vy are independent of each other given v0.
I gave students a choice for their final projects. They could try to re-create one of the projectile apps I've made or they could design their own. They all opted to design their own. I've got everything from monkeys flying through a castle window to slow pitch softball to tossing paper in a trash can. It's really cool to see them make lists of what they need to do, decide which parts of the applet they want to be defined using sliders and have them manage time by deciding which parts of the problem to work on in class and which parts can wait until they get home. (Note: Middle schoolers try to paint the walls and hang pictures before the foundation is built) This has been a great opportunity to talk about how to actually plan a project. They have to work this stuff out on paper before they are even close to being ready to put anything into the computer.
The math they are dealing with behind the scenes here is phenomenal. I had a couple of groups solve:
h = -16t02 + v0sin(α)t0 
by plugging the variables into the quadratic formula because they wanted to find a way to make the animation stop at a certain point.
I'll post their projects once they're completed.
If you'd like the .ggb and .html files for the applet.
 We had to use t0 because we'll need it for animation later. It made the equation a bit more complicated, but they worked it out.