Quantum Minigolf is nearly the same as the game minigolf - except that the ball obeys the laws of quantum mechanics.
Such a ball can be at several places at once. It can diffract around obstacles and interfere with itself. Apart from that, the rules are the same: You can play on various tracks involving various obstacles. You hit the ball with a club and try to kick it into a hole on the other side of the track.
To play quantum minigolf, download the game in the download section. It is a GPLed C++ program, which has been tested under Windows and Linux. It features a simple user interface. You can add your own tracks by editing them in any image editing software and saving them in bmp format.
There also exists a (virtually) real version of quantum minigolf. It permits to play with a real club and a ball which is projected onto the track by a video projector mounted on a 2m (6ft) high tripod. The club is marked by an infrared LED, and detected by a webcam next to the video projector. An image recognition algorithm in the quantum minigolf software computes the club position and feeds back hits into the simulation.