For my senior design project in software engineering, my group and I created a website. You can check it out and register at http://www.trackthismix.com. The premise is finding and making mix tapes or mix cds. A user will make a mix cd and create a page with the track list and a location where they are planning on leaving it. After submitting this information, the user is given a unique ID number to write on the cd. The user writes the number and the website on the cd and leaves it in the location specified.
When someone finds the cd, they can go to the website and enter the ID number to view track information. If they choose to register for the site, they can also leave comments about the mix and track the cds they've found and the ones they've made. Registered users can also search for cds left in their area and see the results shown on a Google map.
Check out the site and see what you think!