Back in February I coded up a userspace driver to control a USB foam missile launcher manufactured by DreamCheeky. The video below shows one of the example programs in action.

The code being executed in the video is from basic-sync.cpp, the simplest demonstration I could think of:

Missile *launcher = new Missile(launcherHandle);

launcher -> async = false;
launcher -> move(ML_DOWN, 1000);
launcher -> move(ML_UP, 1000);
launcher -> move(ML_LEFT, 1000);
launcher -> move(ML_RIGHT, 1000);
launcher -> fire();

delete launcher;

The USB driver uses libusb, and was coded in response to this trivial bug not being fixed in the Ubuntu repositories for over a year.