Podcasts are my favourite things ever. I would highly recommend Doogtoons (very funny 2-3 minute cartoons). I also get Real Time With Bill Maher, which when listening to in public, makes me look crazy because I'm often listening attentively and/or laughing.
As much as I like to deny it, I also really love the Hi My Name is Mark podcast (with Blink 182's Mark Hoppus). I have honestly gotten so much good music from there.
Other favourites include The History of New Music, Suicide Girls, Evolution 101 & the indiefeed.com podcast. I love free crap guys.