You may have heard of the sport of hypermiling, where you try to maximize the number of miles that you can travel on a tank of gas. Now that's far too much work to contemplate for most of us, but how would you like to be able to see what mileage your car is getting from moment to moment?
Via Instapundit, here's the ScanGauge II, a cool little device that plugs into your car's computer access port and gives you an instantaneous readout of your MPG. Going up a hill? Mileage down. Pedal to the floor? Mileage down.