Hydrocoin, whenever you want water simply open your tap and activate your smartphone app to deposit coins to the local M.U.D. at a varying rate starting at 1 coin / liter. As soon as the block chain completes proof of work your tap will begin to flow. If attempting to get water at a time of high blockchain volatility or transaction demand, please allow 12-48 hours for processing. It is recommended not to use Hydrocoin during hours of peak operation such as mornings or evenings due to expected load related delays.

However, I do like the ideal of literal bucket arbitrage.