We asked pandora founder Tim Westergren for his favorite musical invention:
'I recently discovered the iRealBook iPhone application. The app contains bass, drum and piano tracks for all the jazz standards. It's the perfect technology for a practicing musician: high-quality digital audio, mixable, transposable into any key and completely mobile. Now every aspiring musician has a backup band in their pocket. Man, I would have killed for this back in the woodshed days.'