Excited Umphrey’s McGee fans waited eagerly outside of the Calvin Theater in Northampton Friday night. The always-surprising Chicago-based band managed to rouse nearly everyone in the large, seated auditorium into enthusiastic motion at this fast-paced, dance fueled show.

The group, known for their refusal to repeat themselves, kicked off their performance with “Jazz Odyssey,” an upbeat song with an infectious groove and, of all things, rapped vocals. Audience members witnessed not only the group’s technical facility with tight, complicated rhythms but also their improvisational communication as they traded rhythmic and harmonic ideas. Listeners who are unfamiliar with Umphrey’s music may not have necessarily known which portions of the music were improvised but this visual communication was a good clue. Most of the band members have been playing together for over a decade and are familiar enough with each other’s playing style that improvised solos sometimes sound composed and vice versa.

As usual for an Umphrey’s McGee show, the stage lights were constantly moving and dancing along with the energetic crowd. The dazzling display created a visual experience that even those seated in the back of the auditorium could enjoy.

Mike Mirro’s cowbell rhythms pierced through the organ-tuned keyboard sound on songs like “Resolution.” His grooves involve a uniquely sophisticated use of cowbell which is arguably, by its nature, a goofy sounding instrument. The cowbell served its usual purpose of getting the crowd moving to the pulse, but Mirro used it in such a way that was more musically interesting than merely hitting it on every beat. One might even say that his percussive stylings worked the audience into a bit of a fever.

Brendan Bayliss and Jake Cinniger played acoustically on one of the band’s originals as well as a cover of Led Zeppelin’s extraordinarily mellow “That’s The Way.” This briefly shifted the mood and pace of the show from a straightforward dance party to a more cathartic listening experience. This shift in tempo and dynamic provided a nice transition between the two sets. “That’s The Way” has long been in the band’s repertoire of covers, but according to their fan sites, it has been quite a while since they have last played this one.

The second half of the show involved yet more covers as the band played Eric Clapton’s “Layla” and an interlude of “Every Breath You Take” by Sting. There is a feeling of solidarity among fans when the band plays the first few notes of a song, and that ripple of sound goes through the crowd as they recognize the song and look forward to hearing it in its entirety. But as a jam band, and an original sounding one at that, Umphrey’s McGee added something new to each of the familiar songs.

Not surprisingly, the band returned for an encore. They played “Hurt Bird Bath,” an aggressive fan favorite off of their 2002 album “Local Band Does OK,” which gave the audience a second (or third) wind before sending them reluctantly back outside into the cold evening.

Emily Butler can be reached at [email protected].