The mouse can be used to move the scene around and to zoom.
q, w, e, a, s, d, z, x, and c will change to different axes of rotation.
r will remove one block at a time from the scene. After they are all gone it will start putting them back; if you do it fast enough it will crash the program (and this is a bug, not my fault.)
The arrow keys will change the speed of the spin and the distance from the center.
If you like you can download the jar file and you can specify things like the number of cubes on the command line.
If this isn't working, you can also launch using web start.
This is probably my favorite; it shows a bunch of java3d color cubes rotating around a central point. The program was written to demonstrate a java3d bug dealing with the removal of objects from the scene, but it allows you to alter to rotations and seeing the patters that are formed can be fascinating.
See more programs or go home.