Thank you for playing :) A fail handler does sound like a good idea. Control is remote control only, without audio (saves your bandwidth if you're driving your media center with this). Endless will recycle historical tracks if there are no requests.
It seems difficult to monetize such a thing (other than using affiliate links, etc). When I find a bit of spare time, I do plan to clean up the code and make it open source. Meanwhile, you could find the previous version at https://github.com/jyio/jamwithfriends
I, too, loved turntable.fm and wanted something similar. When you request a track (add it to your list), you upvote the track; if votes >= median, it gets queued in the master playlist (thumbnail appears in the header), or else it appears gray on your list.
It actually tries to detect country-restricted tracks and proxies them (so it's good that there aren't too many of these... yet).
When I encounter one of those, I refresh with the console open and find a request to *.googlevideo.com/videoplayback returning 403 Forbidden. It's hard for me to debug this in the US, but I'll look into it.