Do you really need to listen to a morning DJ crank-call an elderly woman who believes she's speaking to Lady Gaga? Upgrade your commute—and sharpen your mental acuity—with an audio version of a classic from your library, or get a subscription to Audible and listen to the freshest business titles (my favorite: The Power of Habit). Another overlooked option is the offerings from The Great Courses (everything from physics to the history of the ancient world, taught by big-name professors), the lessons of which often apply to the work world (my favorite: "Secrets of Mental Math").
Don't forget hands-free language programs. Mary Alice McDonald, who works in music publishing, has been learning Russian during her morning commute. "I like to mentally practice common words and phrases that apply to my commute," she says, especially when another driver cuts her off. "You can only imagine how colorful my vocabulary is becoming." Not to mention: learning a language spoken in a country where your organization does business can give you a leg up when it comes to advancing.