I don't think I've mentioned this before... but it seems eminently plug-worthy so I really should have done.
It's the New Humanist Advent Podcasts... a rationalist advent calendar in audio form. Behind each, erm, window there's a short audioclip where someone names the scientist/philosopher/thinker they think deserves to be celebrated.
Alexei Sayle, Stephen Fry, Chris Addison and Eddie Izzard sit alongside science writers like Simon Singh and Ben Goldacre
You can find them on the New Humanist blog, here, and if for some strange reason you're visiting from the future and can't be bothered to scroll back through their blog to find December, you can find a handy collection of all the podcasts here.
My own rather ropey contribution is here... happy Erdősmas.