If music motivates you, GetWorkDoneMusic is a simple web app that can help you focus and power through your day. You can hit play to start an auto-generated playlist from SoundCloud designed to keep you going.
The service uses "fast" and "faster" buttons to pull a pair of SoundCloud playlists populated with hundreds of tracks that are randomised every time you visit the site. The developer also says he's working to expand the playlists to well over 1000 songs so that you won't hear the same song twice. If you hear a track you like, click "that last one was sweet" to hear it again. You can also skip past tracks you don't like with the "gimme the next one cap'n" button.
GetWorkDoneMusic is the handiwork of Ryan Ghods, a university student who built the service web app in one weekend. I listened to the "Fast" playlist for most of the morning without any problems. It's not the only streaming music solution in town, but it's fast, free, and doesn't require signups or downloads. Look it up even if you just want a quick shot of good tunes to listen to while you work.