My colleague Monty regularly produces quite interesting demos for the amazing things  Xiph.org is producing. I really enjoyed his last one, about the various improvements in Opus 1.1. The live Javascript demos are really quite neat.

Check it out: http://people.xiph.org/~xiphmont/demo/opus/demo3.shtml

If you have a long weekend, the other demos in http://people.xiph.org/~xiphmont/demo/ are also worth looking at.