I spend a great deal of time visiting unfamiliar cities, spending days walking, cycling, or riding trains and buses through them. Sometimes the people of these cities speak languages I know; sometimes they speak languages I don't. Either way, during all these hours in motion, my personal soundtrack comes from an iPod loaded with language-learning podcasts. If you'd like to engage in this delightfully mentally stimulating practice yourself — and I highly recommend it — you can get started by browsing Open Culture's collection of Free Language Lessons available online. The list covers no fewer than 40 tongues, and many of the lessons come in podcast form. Should you find yourself in need of shows offering Bulgarian survival phrases, instruction in Swedish expressions and culture, or Polish in one minute a day, here is the list you want. From my efforts in studying Spanish, Korean, and Japanese, I can personally (and strongly) recommend several of its offerings.
Coffee Break Spanish and the more advanced Show Time Spanish, both produced by the Radio Lingua network (out of Scotland, of all places) start you off from an absolute zero of presumed knowledge and proceeds to get you up to "cruising altitude," which I call the point in language acquisition at which you become able to learn from real, untranslated speech. You might then consider downloading a show like Notes in Spanish, and especially the conversationally focused Notes in Spanish Gold. For Japanese, few language podcasts cater to a wider variety of proficiency levels at once than does JapanesePod101, which I supplement with Japanese national broadcaster NHK's lessons (which also come taught in quite a few languages besides English.) And for Korean, the language that first cultivated in me this whole intellectually and socially thrilling learning addiction, you can do no better than Hyunwoo Sun's Talk to Me in Korean, quite possibly the most thorough, frequent, slick, and entertaining language-instruction podcast of any kind. Listening to these shows has convinced me that every moment spent not acquiring a new language is a moment wasted. But even if you don't believe anything that extreme, it's still a lot of fun. And doing it through these free podcasts, you certainly can't argue with the price.
Here's our collection once again: Learn 40 Languages for Free: Spanish, English, Chinese & More