Toby Keith w/ Eric Church

It's hard to think of Toby Keith as the granddaddy of country music, but at 49, with 13 studio albums, 19 No. 1 country singles and countless awards (and a grandchild in real life), Keith has earned that title and then some. Whether it's the patriotic fervor of “Courtesy of the Red, White & Blue (The Angry American)” or tongue-in-cheek tunes of good times (“I Love This Bar” and the Willie Nelson duet “Beer for My Horses”), the Clinton, Okla., native is passionate about his beliefs, good times and otherwise. Keith likes to change things up, too: He's toured with the likes of Ted Nugent and sang a duet with Sting on a cover of “I'm So Happy I Can't Stop Crying.” Fans should make a point of coming early to see opening act Eric Church, another talented country singer-songwriter. Church will feature songs from his upcoming third studio album, Chief, which is due for release three weeks after his Summerfest appearance. (Harry Cherkinian)