I would start a derivatives trading firm specializing in securitizing consumer products. First: a gasoline-contract, so people could hedge their gas purchases f

I would start a derivatives trading firm specializing in securitizing consumer products. First: a gasoline-contract, so people could hedge their gas purchases for the expected life of any car they bought (and never care about gas again -- until it was time to buy a new car). Then, personal market-makers, which would, e.g., try to buy more of foods you liked when they were cheap, suggest alternative venues for entertainment and dining, etc. This would allow people to 'sketch' their demand curves for lots of goods, solving part of the socialist calculation debate and allowing me and my friends to spend our time doing something besides being obnoxious libertarians. Interesting problems this could solve: over-investment and under-use of transportation (lease your bike to a courier from 9, when you arrive at work, until 5, when you leave -- charging a different leasing rate depending on the reputation of the courier, of course); estimating the effects of changes in excise taxes; having a better idea of when it's worth it to spend X minutes for a Y% chance to save $Z; etc.