If you are any good with those old “magic eye” posters and interested in anatomy, check out vovel123’s incredible gallery of stereogram CT scans. There are nearly 700 incredibly cool stereograms waiting to be seen in all their 3D glory.
These take a little practice to get right, but luckily after several years of reading biochemistry papers I can do stereograms in my sleep (you biochemists and crystallographers out there know what I’m talkin’ about, right?).
Click the images to make them big, for starters. If you allow your eyes to cross a little, then the two outside images will cross over in the center. Relax your eyes there and don’t fight the weirdness. You’ll be seeing 3D before you know it!