One of the brainier events during this Winterskol weekend, is the presentation by the Aspen Center for Physics called "Nature's Smallest Rotary Engine." Physicist Kazukiko Kinosita from Waseda University in Japan will discuss the science behind how and why we eat and breathe. Heady stuff at 8,000 feet! The lecture begins at 5:30 at the Wheeler Opera House, with a Physics Cafe beforehand in the lobby. For details on this free event, call the Wheeler Opera House at (970) 920-5770.