Little Atoms: http://www.littleatoms.com/
A bit lo-fi compared to Point of Inquiry or Skeptic's Guide, but the interviewers always know their stuff and ask enlightening questions, while the interviewees without exception incredibly interesting and thought-provoking.
Seriously, look at the caliber of guests they've had on the link above.
Recently the Marcus Chown episode had the /best/ explanation for the arrow of time that I've ever heard.
Edit: Follow littleatoms on twitter!