Well, we didn't do this on commutes, but a few years ago, a friend and I used to go on what we called Marlboro rides.

We would actually go on our regular training rides, but we would stop and pick up empty Marlboro packs and boxes. We'd score the miles on the packs and cash it in for cool Marlboro schwag. I got a decent backpack, a lighter for the backpack, a rainjacket, a very nice duffel that I use all the time when I travel. A poker card set in a cool little carry pouch, and other stuff I can't remember. My friend got the boombox, a inflatable kayak. the tent and other stuff.

Man, I was always surprised at how many packs people threw on the ground. I used to carry a daypack so I could carry them all.

Sure wish they would bring that back.