When you need to focus, it helps to have the right music. Music For Programming is a handy little online tool with an hour-long playlist of non-vocal music designed to help you stay in the zone.
You can head to the tool at the link below and start playing directly from the web page. It contains 44 tracks that are designed to play in the background while you program (or, presumably, do other kinds of work) without distracting you. As the site explains, the goal was to put together a playlist that could disguise itself as background noise while still being stimulating. If nothing else, it's an excellent diversion from the usual spate of suggested stations you find on Pandora or Spotify.