I think it's a great Idea I'm working on something similar at the moment called Artcoin, it's a peer to peer painting currency, instead of contributing computational power each peer has to make the picture a little bit prettier. Once a user on the block chain agrees to buy the picture because it's lovely for $2, the difficulty doubles and the next artwork needs to attract a buyer at $4. There's a predetermined amount of artwork to be created (30) as the last one's got to be an absolutely blinding masterpiece that no one can top valued at $1,073,741,824   

I'm also working on BC coin (bible code coin) where each peers hashing power goes towards finding revelations about the future hidden inside War and Peace every time we find something trippy an automated email gets sent to the sunday mirror in return for cash split among those who contribute hashing power.