Four days on a 700-acre Tennessee farm, 80,000 people, and a lineup that has been staking claims about American music since 2002. Bonnaroo gets this right every June. The experience at Bonnaroo is harder to explain than it is to feel. Walking into Centeroo — the central festival grounds — for the first time, you're hit by scale and warmth simultaneously. Multiple stages blast sound across the Tennessee heat. Art installations catch light at unexpected angles. Strangers hand you things with no expectation of return. The crowd skews eclectic: first-timers in bucket hats, veterans who've camped here fifteen years running, families with kids in tow, groups of friends who planned …