MPEG1 Video Decoder in JavaScript - PhobosLab
http://phoboslab.org/log/2013/05/mpeg1-video-decoder-in-javascript
An MPEG1 decoder sounded like a relatively simple and fun weekend project. While the real world use cases for this are of course a bit limited, I still learned a whole lot about video codecs in the process. The size of the source is just around 15kb gzipped and the performance is quite okay-ish - a 320x240 video easily plays with 30fps on the iPhone5.