The FBR Open (www.phoenixopen.com) is the biggest party in town — and the largest event on the PGA Tour, luring nearly a half million people to TPC Scottsdale over the course of a week.

The infamous annual event, usually held in late January or early February, is not your traditional, polite-applause tournament. In fact, it’s more like a nightclub on the fairway. You’re as likely to see seniors with scorecards as 20-somethings in tube tops and heels, barhopping from beer gardens to VIP skyboxes. The plentiful bars and young crowds fuel a raucous party atmosphere, so much so that Tiger Woods, who sunk a legendary hole-in-one on the 16th hole, has vowed not to return.

TPC Scottsdale’s Stadium Course was specifically designed to accommodate an “unlimited number of people.” And by the final day, that can mean as many as 50,000 fans gathered around the 18th hole to watch pros like Phil Mickelson and Vijay Singh sink a tournament-winning putt.

Golf is only part of the draw, though, with half the crowd arriving when the sun sets and the putting is over. These latecomers flock to the Birds Nest, a party tent where big-name bands entertain thousands of carousers with drinks.

The Thunderbirds, a group of the Valley’s leading businessmen, have hosted the event since 1939, making it one of the five oldest events on the PGA tour. It’s the philanthropic group’s biggest fundraiser, netting more than $50 million for Arizona charities. Admission begins at $25 per day, though there are additional fees for skyboxes and entrance to the after-hours Birds Nest.