This has to be a tie between re-frozen slushy uneven dirty ice stuff just right of the nicely plowed pavement, and super-glassy ice with a dusting of fresh powder - SalshShark
The stereo pairs are cool, and the red/cyan anaglyphs are okay. But having them alternate is just plain creepy.
I wish they would just let you see the pairs in large images on a black background so you can just cross your eyes and get the full effect without any gimmickry. That would be much better. You can test it here. Cross your eyes and look at the two images, relax and a third 3D image will appear in the center.