The Lukas Canade optical flow demo is really cool [0]. Stick blobs to your face and they track around in the same spot.

[0] http://inspirit.github.com/jsfeat/sample_oflow_lk.html

I can't stop staring at the edge detection filter[0]. Very cool.

0: http://inspirit.github.com/jsfeat/sample_canny_edge.html

I like image processing and cache pool feature in this JSFeat - really useful!