Doing what you want with your own device? Us Android people have been doing that for a while. I've been running Cyanogen mod on my 2 year old G1, adding features TMobile refuses to add. I have an option that I can check that allows installation of packages outside of the market.
Planet Moron has a post on the city of Alexandria, Virgina using microchips in recycling bins to track usage for "educational purposes."