I recently came across a web site that make Custom Tire Covers called Threads to Treads. If you have an exposed spare tire you want to protect from the weather and add some artistic flaire, this is the way to go. They are made by the "Sweat Shop Girls" in Redding, California and the only limits is your imagination, so get yours today. Below are the ones available for sale and my all time favorite is the Darth Vader one, and if you like these they have more in flickr.
1) Darth Vader Tire Cover
2) Burning Man Tire Cover
3) Cheshire Cat Tire Cover
4) Rolling Stones Tire Cover
5) Puffy Lips Tire Cover on the Lady Bug Art Car
6) VW Tire cover on the Fahrvernpüssy Lounge VW Art Van