I walk 3-5 miles everyday and find that listening to podcasts helps keep monotony at bay. It's also a good way to take my mind off pressing concerns and maybe learn something in the bargain.
My favorite right now is 99% Invisible. "Ever wonder how inflatable men came to be regular fixtures at used car lots? Curious about the origin of the fortune cookie? Want to know why Sigmund Freud opted for a couch over an armchair? 99% Invisible is about all the thought that goes into the things we don’t think about — the unnoticed architecture and design that shape our world."