What was the most Badass JavaScript demo of 2011?

No contest in my opinion. http://bellard.org/jslinux/

PC Emulator http://bellard.org/jslinux/

The native JS h264 decoder was pretty awesome.

https://github.com/mbebenita/Broadway

Some candidates may be found here:

http://www.netmagazine.com/features/2011-review-20-sites-pus...

http://www.netmagazine.com/features/2011-review-20-html5-sit...

Admittedly I just found this when somebody linked to it in the "20 sites that pushed JavaScript to the limit" discussion thread.

http://mrdoob.github.com/three.js/

Twitter mobile bothers me. I just want to see a few tweets, not wait 10 seconds for all the javascript to load and ajax calls to complete so I can see the content I want.

Some ideas: pdf.js, jsmad, h.264 and webm in JS, webgl visualizations, useful libraries, etc.