I've been intrigued by the idea of establishing a blockchain for the sale and transfer of art. It has the similar characteristics of currency: several parties who do not have trust, a finite number of items (at any point in time).

A challenge would be to devise how new items are added - are there a few nodes (trusted galleries) that can add new pieces.

This would prevent a work that is in a private collection somewhere from being "discovered" by a forger. Anyone would be able to query the ledger and see that a different collector currently owns the piece.