Covering everything from the quest for supersymmetry to pondering time and motion, the brainiacs at the Perimeter Institute for Theoretical Physics are gladly offering audio recordings of recent lectures for free via their website. Their free audio section features over 20 heady lectures available in MP3, Flash and Windows Media formats for you to stick straight on your iPod (or Zune) and ponder while working your way to healthy at the gym.

Hear more: Public lections from the PITP