In keeping with that theme, organizers have scheduled performances by dozens of pop, classic rock, country, alternative, gospel and Mexican music groups.
"American Idol" winners Kelly Clarkson and David Cook will be performing, as will runner-up David Archuleta.
Also scheduled to take the stage are Melissa Etheridge, Los Tucanes de Tijuana, Phil Vassar, Poison's Bret Michaels, Loretta Lynn, The Guess Who, The B-52s, Switchfoot, Clint Black, Creedence Clearwater Revisited, KC and the Sunshine Band, Joan Jett and the Blackhearts and Smokey Robinson.
Opening day festivities include a car show, dancing horses, beer sampling and performances by the "Heroes of Woodstock," including Jefferson Starship, Canned Heat, Country Joe McDonald, Big Brother & The Holding Company and Tom Constanten of the Grateful Dead.
The San Diego County Fair annually draws more than 1.2 million people. It runs through July 5 at the Del Mar Fairgrounds, but is closed on the first two Mondays. Gates open at 10 a.m.
Admission is $13 for adults, $7 for those 6-12, $7 for seniors 62 and older. Children 5 and under get in free.