Umphrey's McGee is a band that dwells in different musical realms.

There has even been a term coined for what the Chicago-based sextet does - "improg", a combination of improvisational and progressive rock music.The improvisational part appeals to fans of the jam band circuit, to which Umphrey's McGee (the band took its name from a relative of guitarist Brendan Bayliss) is often linked. The band demonstrated its stamina Friday night at Penn's Peak with a three-hour performance, including two sets and an encore.The progressive side of Umphrey's comes out through influences such as Genesis, Frank Zappa's Mothers of Invention and Pink Floyd, although the band's choice of covers reveals a diverse musical personality.One tradition Umphrey's has carried on from the prog rockers is a dazzling light show, which was on full display to the delight of the 1,100 Umphreaks at the Peak.Light shows can be distractions if they are too overwhelming, but Umphrey's uses theirs at the service of the music. The swirling illumination is synchronized to the sounds generated onstage, so that every shift in rhythm and tempo provides its own colorful effect.That sound is guitar driven, with Bayliss and Jake Cinninger providing slicing riffs around Ryan Stasik's propulsive bass lines. Drummer Kris Myers and percussionist Andy Farag shape the rhythmic pulse, while Joel Cummins completes the musical picture with his keyboard work.The first set contained "Atmosfarag", primarily the creation of its namesake for his synth drum machine (the liner notes for the band's "The Bottom Half" rarities album calls it a groove box). A long run bookended by "The Bottom Half" then ensued, with a trio of tracks from Umphrey's "Local Band Does OK" album ("2nd Self", "Water" and "Andy's Last Beer") and "Intentions Clear" (which has popped up on both "The Bottom Half" and "Safety in Numbers" CDs).Wedged in the middle of all that was a showcase for Cummins, who did vocal and piano honors on a rendition of Supertramp's classic "Bloody Well Right".Umphrey's opened the second set with "Miss Tinkle's Overture" from its "Anchor Drops" album, then went into an extended jamfest that included songs "Words", "Last Man Swerving", "Utopian Fir". "Sociable Jimmy", and "Walletsworth", which spanned their career. The titles may not be familiar to those on the outside, but the crowd gyrated in delight for practically every note, roaring its approval after the band segued into something different.A mosh-up of Led Zeppelin's anthemic "Immigrant Song" with the kick of White Zombie's "Thunder Kiss '65" right in the middle of the set really got the audience jumping.Umphrey's closed set number two with "Cemetery Walk" from last year's "Mantis" album, which demonstrated the band could cut it in the studio with its prog rock brethren.It would have been great had Umphrey's performed the magnum opus title song, but it had done so the day before and it stuck to its usual plan of not repeating itself each night, or even at the same venue ("Mantis" was the encore at Umphrey's Peak show last year).The encore was "JaJunk" from "Anchor Drops". Umphrey's gave its followers their money's worth, and there's no doubt a number of them followed the band to Asbury Park, New Jersey for another shot of compelling sights and sound.