Nice! I'm thinking my idea of a self-adjusting currency that uses a peer to peer proof of work algorithm which solves useful NP problems as a side effect and incorporates automated credit ratings based on debt repayment and contract fulfillment rates is probably in the 3 range. But if I hook it up to a protein folding game that teaches advanced biochemistry to akrasiatic gamers as a side effect it could be boosted up to the 6 range.
I trust you've looked into Ripple? It strikes me as fairly interesting, though the implementation is, at present, uninspiring.
From Hacker News.
This made me laugh, but from the look of it, I'd say there is little work to do to make it serious. Personally, I'd try to shorten it so it is punchier and more memorable.