I have this idea for a collective art project. It involves the making of mix tapes based on different themes/ideas, i.e. songs with titles that are named after women or songs that start with "I" or song from 1978 etc., and also have arty cases. Actually there are two ideas:
1. Somehow establish a network of people and trade mix tapes within that network. (This idea is newer)
2. Leave the tapes in public places hoping that someone will pick it up and listen to it.
The second idea involves more chance, and a high likelyhood that your tape will get smashed or thrown in the garbage. But there could be a blog for the project, and operatives in different cities, and the tapes wouldn't have tracklists with them, but if you found the blog you could look up all the information the maker wanted to put with the tape, including motivations for picking each song and what albums they came from or how they got in to that band etc.
I'll have to think about it more.