What is it like to be running on a snowy, remote jeep trail in December, getting caught in a whiteout, and spending eighteen hours shivering in a snow hole? Is it a good idea to promise a friend you'll buy a mountain bike and ride with him 2500 miles along the Continental Divide, or help another friend, who has Parkinson's disease, race 100 miles on mountain trails? If you like armchair adventures, come along and experience running across the Grand Canyon and back, at high altitude in Colorado after recovering from cancer, 500 miles across Washington state, and the largest ultramarathon in...