If things look a little greener around here this April, there's a good reason. Our editorial staff is busy expanding the ideals of Earth Day into a month-long celebration of energy conservation, alternative transportation, recycling tips and about a million ways you can be a better friend to the planet. Welcome to Green Month, Milwaukee.

It's taken nearly three years of driving our 2005 Toyota Prius, but yesterday I refueled our first complete tank that achieved 51 miles per gallon.

That's a big deal, since the previous best mileage ever came on a perfectly flat, highway trip to Detroit right after we bought the car. That tank averaged 50 mpg, and was the first and last time we topped that elusive mark. Usually, the very best we do is about 47 mpg, when it's warm but not too warm (the air conditioner hurts the fuel economy). The worst we do is in the dead of the winter, when it takes longer for the engine to warm up and the battery to operate efficiently, and we drop down to the mid 30s.

Keep in mind, when we bought the car, Toyota boasted its EPA ratings of up to 60 miles per gallon in the city. But everyone knew that was pure fiction, and only the most dedicated hybrid drivers have ever pulled that off. Even when driving very conservatively, the car performs much less efficiently, which is why the new "CAFE" ratings say the Prius will get 48 mpg in the city, 45 on the highway, and 46 combined.

While it sounds like splitting hairs, it really isn't. When we bought the car in 2005, gas prices were maybe $1.75 per gallon. Industry observers said the premium price consumers pay for a hybrid engine would take years to be realized from cost savings in gas. After all, the Prius is easily the chintziest $23,000 car on the market, cheap and plastic-y like the Tercel I drove right after college. It has little to no acceleration, performs terribly in the snow and basically looks ridiculous from all angles. At times, it's just embarrassing to drive.

But that's not why we bought it. Now that gas is pushing $4 per gallon (and rising), those mileage numbers really add up. Yesterday, $32 filled up the tank, which gets about 450 miles -- probably more if I pushed it.

Say what you want -- or say nothing at all -- about the environmental benefits of driving a SULEV (Super Ultra Low Emissions Vehicle), but you can't deny that this silly-looking car helps where most Americans need it most: in the wallet.