Steven Hawking did not have to attend a Rainbow Family reunion to understand chaos theory, but for nongeniuses the experience can be helpful. For starters, there is nothing like a naked, hairy 50-year-old man squatting in a meadow to remind you of the power of spontaneity. But individual expression aside, the Rainbows have turned the Uinta Mountains into an outdoor laboratory demonstrating how, with time, order can emerge from undesirable randomness. The Rainbows are a vast, leaderless collective of latter-day hippies, anarchists and street people that congregates once a year on public lands to espouse peace and denounce the trappings...