Ambient Devices' various "thin data" products, but Mark Martinez, a Southern California Edison power station manager, has probably hit upon the most interesting application we've seen: by reprogramming the device to reflect energy usage and costs, customers in his 120-person test program managed to reduce their energy consumption by 40 percent. Martinez chalks the results up to the "sentinel effect," saying that ""It's nonintrusive. It has a relatively benign effect. But when you suddenly see your ball flashing red, you notice." Ambient Devices actually sells a similar product called the EnergyJoule, and we've seen some other monitoring attempts before, but we think we like Martinez's hack better -- it brings a little mod flair to living green. Hopefully he'll let us know how he did it soon.