This is the side project I'm using to learn programming. I built the first(current) version using PHP + Javascript without any frameworks. The upcoming version is rewritten in Rails and Backbone.JS (which I think was a mistake). The new version has additional features like playlists, mobile-compatibility, the ability to resize the video, bookmarkable URLs, etc.
Guildsmanship: Battle-Scapes - http://www.guildsmanship.com.
As complete an implementation as can be of the Open Game License SRD in a tactical team battle system.