It’s between 11 p.m. and 1 a.m. on a cold Saturday in March and the All-American Rathskeller is full of a variety of characters. There’s some students tricked out in over-sized leprechaun hats and shiny, green beads getting an early start on Saint Patrick’s Day. Others are wearing their Saturday night best while students in zip-up hoodies and work boots order a few more Budweisers.

They all crowd around a dark stage where the band Memphis Hat is falling into an undeniable groove. The heads in the crowd begin to bob in unison to a Grateful Dead cover, taking breaks only when they need another sip of their $2.50 Jack and Cokes.

“I like the fact that the more we play [in State College], with every show it seems like there’s a couple more people that will latch on and get down with what we’re putting down,” says drummer and Penn State alum Steve Clarke.”It’s real cool to provide some sort of outlet for the kids who want to go out and see live music and some jamming and original stuff as opposed to someone playing Keisha and Justin Bieber. And I’m sure that music is popular in its own right, but there’s certainly a niche for jam band music.”

Memphis Hat formed in the spring of 2009 while its members were attending Penn State. Clarke wasn’t in the band back then, but he says his friendship with guitarist J.D. Dronson and guitarist/vocalist Matt McGovern made it an easy transition when the band decided to change the lineup about two years ago. Dronson’s cousin, Rory Flynn, took over on bass, and the current lineup of the band was complete.

During Clarke’s senior year in 2012, the band began to build a small, but enthusiastic fan base with recurring gigs at the Shandygaff and the Phyrst that showcased its combination of classic rock and blues with a jam band twist. The band’s set list includes a mix of originals and covers by artists like The Beatles, The Rolling Stones, The Black Keys, The Temptations, and Creedence Clearwater Revival (just last week they tore through a revved-up cover of “Straight Up and Down” — the theme song from Boardwalk Empire).

“Most of the sets are about fifty-fifty with originals and covers,” Clarke says. “We’re trying to incorporate more originals as they get more popular and as we get more practice with them, but we still definitely mix in enough covers that some people will recognize if they don’t know what the other tunes are.”

Now, with the members scattered throughout Pennsylvania (Clarke moved back home to Horsham after graduating last May, Dronson is attending LaSalle University for a graduate program, Flynn is graduating from Millersville University in the spring, and McGovern is finishing up his senior year at Penn State), the band plays about three Saturdays a month at the Skeller.

Even though practicing has become an issue because of differing schedules, the band manages to put together three gnarly sets on minimal rehearsal. Before a Skeller gig, they all get together Friday afternoon at McGovern’s apartment where they have a quiet, sometimes unplugged rehearsal (the cops have shut them down before over noise complaints). The day of the show they’ll go over the set list and, if they have time, try to learn a new song. But for how little they get to practice together, the band sounds seasoned. Dronson and McGovern trade off shredding guitar solos while Clarke and Flynn keep the rhythm section tight and a little funky.

When he’s not working, Clarke manages press contacts and bookings for the band. He also puts together press kits, emails bars, and sends out sound clips in an effort to get the band more exposure. At gigs, the band also gives out free copies of their 12-song demo of originals that they recorded in early 2012 at East Coast Recording Company in Warminister, Pa.

Once everyone graduates, the band plans to move their base of operation to Bucks County so they can focus on getting more gigs in the Philadelphia area and along the shore.

And Clarke says the occasional show in State College won’t be out of the question.

Memphis Hat will be performing at the All-American Rathskeller tomorrow at 10:30 p.m. Cover is $3. Bass solos are free.