Pandora, the grandaddy of music streaming services, has a pretty cool feature for its paid subscribers.
You know how Pandora works. It calls itself a music recommendation service, though in reality it doesn't recommend as much as it drops stuff take-it-or-leave-it. More precisely, I would call it an algorithmic automatic service.
If you're a paid subscriber, specifically a Pandora Plus customer, you have tweaking control of your library of stations -- which you can listen to for hours ad-free. But what I find invaluable, and the only way I use Pandora any more, is the option to shuffle your stations. With that, Pandora delivers its automatic, on-the-fly queue through random polling of your entire library.