O'Neill and Rigby met seven years ago in a laundromat in Chamonix, France. Since then, they've launched 12 major expeditions, climbing and skiing peaks from Argentina to Lebanon. What sealed their friendship, in addition to a shared addiction to high-altitude masochism? Five storm-racked days stuck in a snow cave on Russia's 18,510-foot Mount Elbrus in 1995. "It's not just that we climb together," says Rigby. "We can be tired, cold, and hungry, and still enjoy each other's company." BIG MOMENT: A 2005 ascent of 26,906-foot Cho Oyu, completed without Sherpa support (read: mega load hauling). ROLE PLAY: "I'm better at rope skills and crevasses, and I ski with more confidence," says Telluride-based O'Neill, 33. "Kasha's better at route finding." "Hilaree burns hot," says 36-year-old Rigby, who lives in Salt Lake City. "I get through by staying steady." THE MARTHA FACTOR: "Kasha might forget that extra T-shirt," says O'Neill, "but she always brings lavender oil so our tent doesn't smell." UP NEXT: Northern Myanmar or the Indian Himalayas. "Our next trip will be off the beaten path," says O'Neill. "A return to our old days of adventure."