For more than 15 years, the members of Greensky Bluegrass have created their own version of bluegrass, mixing the acoustic stomp of a string-band with the rule-breaking spirit of rock 'n' roll.

The band, which includes Anders Beck, dobro; Michael Arlen Bont, banjo; Dave Bruzza, guitar; Mike Devol, upright bass; and Paul Hoffman, mandolin, comes to Penn's Peak at 8 p.m. Jan. 26."You can call us an acoustic ensemble, or a drum-less rock band, or a rock 'n' roll bluegrass band," says Hoffman. "All of that shifting identity has taught us to cover a lot of ground."Formed in 2000 in Kalamazoo, Michigan, the band got its start playing living rooms and open mic nights across the Midwest. By 2005, they were touring nationally, and by 2006, they were playing the first in a series of appearances at the annual Telluride Bluegrass Festival.They spent most of the following decade on the road, fine-tuning a live show modeled not after the toned-down production of traditional bluegrass, but the full-on spectacle of rock."We play two sets of music every night with a big light show, and really care about creating a large scale production," said Bruzza. "The goal isn't just to play important music. We want to cultivate an experience, where people can escape from their everyday lives for a minute and put their worries aside."Playing as many as 175 shows a year, Greensky Bluegrass has graduated to headlining status at some of the country's most iconic venues, selling out amphitheaters like Red Rocks and world-class auditoriums like the Ryman.They've become a regular name on the festival circuit, too. Supported by a grass roots audience whose members often travel hours to see them, Greensky Bluegrass is still a proudly independent act, enjoying the success of a major-label act without giving up complete control of their own business.Also at the Peak• Sunday, An Evening with Umphrey's McGee, 8 p.m.• Jan. 27, Satisfaction - The International Rolling Stones Show, 8 p.m.• Feb. 2, moe, 8 p.m.• Feb. 3, Voyage #1, Journey Tribute Band Featuring Hugo, 8 p.m.• Feb. 4, I Love the 90's with The Fresh Kids of Bel-Air, 8 p.m.• Feb. 10, 38 Special, 8 p.m.• Feb. 18, Sweetheart's Dinner Dance with The Main Street Orchestra• Feb. 25, Bruce in the USA, 8 p.m.• Feb. 28, ZZ Top, 8 p.m.• Feb. 25, Bruce in the USA, 8 p.m.• Feb. 28, ZZ Top, 8 p.m.