Try Ice Skating (500 calories)
Many people love walking—which is wonderful, because it's one of the easiest fitness activities to squeeze into a busy day. But others, including a marathon runner we know as well as a former college basketball player, find walking to be stultifying. Those who can't stand to stroll might consider lacing up a pair of skates. Through the mostly nonimpact activity of ice skating, they'll burn almost twice as many calories, and figuring out how to execute a salchow will keep them focused.