I've been mucking around with 3D recently, and have put together an image gallery. I was also amazed to find out about the Pulfrich effect. Very simply, if you hold a dark lens (ie. one sunglass lens) in front of your (generally) right eye, and view a standard video, you'll get a mild, but still effective, 3D effect.
This is apparently because a dark image takes a split second longer to reach your brain than a bright one.
The things that work best are animations that move right to left (if you have the lens over your right eye) across the screen, but a surprising number of things work with it. Some that I've tried are:
Football matches (that generally pan left or right over the field)
Nature programs where an animal is being tracked as it runs
Some games work surprisingly well - Quake2, Plane Crazy - anything drawn in decent 3D.