I donated my car to the Wisconsin Humane Society this year.
Sold paw prints that people could have their names, dogs names, legendsracer.com (thanks Steve) etc. on.
After cost of the new body, vinyl, pictures, postage, etc, I lost about $800.00 doing it. In my case, it can't be written off because it was not a direct contribution, it is a loss while conducting a fundraiser for a 3rd party.
Glad I could help out the Humane Society and have some fun in the process, but I can't afford to do it again this year.