(Since I created this presentation, the Firefox Add-on mystery has been solved: You have to delete cookies and clear the cache to totally remove the YouTube Flash Video Player Firefox Add-on.)
In this video, I show you how to look at this and other YT3D videos in 2D and 3D.
*New* viewing tip: Using a desktop or laptop computer, here is probably the easiest way to watch this video in 3D or 2D: https://www.youtube.com/v/FpaHHUHnoCs
Click the play button, then after it starts playing, click on the cog wheel in the bottom right corner, and all the viewing options should be available by selecting your viewing options (for 3D TV or monitor, virtual reality viewer, stereoscope, 3D glasses, freeviewing, etc).
The YT3D native video file is parallel side-by-side squeezed.
For other viewing methods, here's my "Tools For Watching YT3D Videos" page: https://sites.google.com/site/watchyt3d/tools