That's easy to do if it's a long way on the open highway. But driving through gridlocked traffic in cities or during rush hour that isn't possible... at least for my limited brainpower :)
You could try listening to podcasts - when I was 'commuting' (i was actually walking) to work, I'd listen to something informative and interesting, so I'd arrive at work inspired every day. For example, TED talks, or web tech stuff: http://5by5.tv/webahead