Awesome! I literally had put on my calendar, after the SDK came out, that if after two months nobody had made a dead-simple player like this, I'd do it myself. Glad I didn't have to. ;)

Suggestion for a next step: wrap it inside an OSX .app or Windows .exe that also launches a local webserver on some random port, so you can stream local media to your Chromecast as well. (I mean, for us developers it's easy enough to set up an instance of Apache, but this would let my grandma use it too.)

Edit: question: does anyone know if it's technically possible to cast a video to Chromecast, but leave the audio playing on my local computer? (Necessarily involving some kind of audio delay.)