People go to music festivals for a lot of reasons: to see their favorite bands, to burnish their Instagram feed, to sweatily camp out under the stars. But a group of volunteers came to the recent Bonnaroo Music and Arts Festival in Tennessee for a fairly unique reason: to save uneaten food from being thrown out and sent to landfills. A group of 300 volunteers managed by Clean Vibes, a waste management company that works with dozens of music festivals to make them more environmentally friendly, spent the four days of the June festival helping to compost 230,000 pounds of food that was left over from caterers or that vendors were unable to sell. The volunteers received free tickets in exchange for their work.