This final note today. The sustainable-minded among you who also like to drive really, really fast can take heart from Ferrari today. Businessweek reports the Italian super-car maker is coming out with a hybrid. Two electric motors running alongside a 12-cylinder gas engine.

Price tag: more than $850,000.

Which raises two questions. One: Do people who can pay $850,000 for a car really care how much they’re paying for gas? And two: Does one of you have a spreadsheet that you can help me out with and figure out the payback period for this thing?

How long it would take to save on gas to make up for the sticker price?

Thanks.