On any given week, Music City Roots draws a crowd composed of everyone from college kids to blue-hairs, thanks to the bands, the beer and the easygoing vibe. But this week’s ought to be a particularly interesting lineup when it comes to age appeal. Jason Ringenberg is in kiddie rock ’n’ roll mode this year (rest assured his brand of kids’ music is the sort of stuff their cowpunk-loving parents can dig, too); he released a guest-filled, nature-themed Farmer Jason album in February. Acoustic troubadour Todd Burge also has a pair of new albums, one for adults and one for children. Then there’s wry master of folk idioms Tim O’Brien, who’s just teamed with his sister Mollie and other family members to record an upcoming tribute album to the great and goofy Roger Miller, and Tommy Womack, who makes a roots-rock laughing matter of middle-aged mediocrity on his latest. Ryan Tanner’s the newbie, and the most straight-laced one of the bunch.