Youtube has added native stereoscopic support to their viewer. This has been an experiment for some time, and is nice that it is finally made publicly available.
DEMO: http://www.youtube.com/watch?v=YuxqPuhLBZg

You can choose a number of viewing methods including: red-blue glasses, blue-yellow glasses, side-by-side images, interleaved images, etc.

The most interesting addition (which is news to me) is that it supports 3D viewing with specialized hardware! Apparently there is a stereoscopic video standard in HTML5 that works with Nvidia 3D vision, and presumably more as time marches unrelentingly forward. AFAICT, this is one of the first (if not only) open standards for 3D content, and it's nice to see it on the web platform.

I have a sturdy plastic pair of red-blue (anaglyph) specs that I got for around $2. One thing that I absolutely would like to see with youtube3D is a way to calibrate the red and blue on the display to reduce ghosting. All monitors have different gamuts and display things differently, and I would imagine the same for the filters in the anaglyph glasses. Calibration would make something like this far more effective!