The fifth Bonnaroo Music + Arts Festival in Tennessee, the world's most successful festival, was all about surprises this weekend (15-18JUN06) as Tom Petty, Bright Eyes and former GRATEFUL DEAD star PHIL LESH served up live treats. Petty + THE HEARTBREAKERS welcomed surprise guest Stevie Nicks onstage for a number of songs during their Saturday night (17JUN06) performance at the event. The FLEETWOOD MAC star has signed on to join the rockers when they tour through the US later this summer (06). Meanwhile, SUPER FURRY ANIMALS star Gruff Rhys joined Bright Eyes frontman Conor Oberst onstage and Lesh brought former PHISH stars Trey Anastasio and Mike Gordon together again for renditions of Dead classics CASEY JONES and GOING DOWN THE ROAD FEELING BAD. But the event's biggest surprise came when former The Police drummer Stewart Copeland reformed his supergroup OYSTERHEAD with Anastasio and ex-PRIMUS star LES CLAYPOOL for a brief set. It marked the first time the trio had played live together since 2001. Other highlights from the four-day festival included Radiohead, Dr John, reggae star DAMIEN MARLEY and rapper Common. Bonnaroo was declared the world's top festival last week (ends16JUN06) when all 80,000 tickets for each day of the event sold out.