I have quite a long commute on my way to my university (about 75 minutes) so I was wondering if there's a math-related podcast or something of the sort you'd recommend. Exercises are appreciated as well, but they should be conceptual (or at least light on computations, so I could solve them in my head), since I can't write while on my commute (I don't drive, but trains are awfully crowded here). Any other suggestion is welcome!
As a sidenote, I've taken multivariable calculus and elementary courses covering linear algebra, sequences and series, number theory and a little bit of complex analysis.