Here are some beautifully rendered views of polytopes, and a few more. The rendering program, Jenn 3D, is free and downloadable, (OS X, Linux, Win) and includes some really dazzling fly-about and camera effects as well as tons of high-dimensional models to explore. There's also a mind-boggling possibility of playing Go on boards in projective space. Via the Math Paint blog, which leads to other interesting places...
Minimal surfaces in 3D (red/green, or stereo pairs), with rotate and zoom. If you want to go beyond the eye-candy aspect, here's the obligatory Mathworld link, the classic intuitive explanation, and a raft of additional information. If you like eye-candy, don't miss the ray-traced minimal surfaces and these interesting, but non-minimal surfaces.