Tired of your mundane three-dimensional Rubik’s cube? Want a hands-on activity to help you make sense of the fourth dimension? Download Magic Cube 4D. The interface is really quite intuitive (and that’s saying something considering how un-intuitive the fourth dimension is).
Oh, and if you consider 4-dimensional Rubik’s Cubes too easy to be worth your time, perhaps you’d prefer Magic Cube 5D.