I just listened to the March 14 Scientific American podcast as I rode into work. Near the end they did a story on Nick Goddard, who figured out how many calories are in a gallon of gas, and how far he could ride on that energy. Then he did it. A bit over 633 miles it turns out, though he thinks his heart monitor was telling him he burned more than he did. He thinks the distance is really closer to 900 miles. I'm not sure this has even a little real world significance, but it's almost interesting.
I guess this is old news now, but it's new to me.