Another podcast that I walk the streets to is Radio National's Future Tense. It is sort of hard to explain but in their words it "explores the social, cultural, political and economic faultlines arising from rapid change". It is done in a rather engaging way that make the 1/2 hour go quickly. It appeals to the geek in me and it features a range of interviewees from sci-fi authors to designers. If BoingBoing.Net appeals to you than you should get a kick out of Future Tense.