“Our music is a big meal that takes forever to digest,” says Rob Reich, the accordionist and founding member of the Bay Area klezmer band Kugelplex.

It takes Reich the better part of five minutes to explain the name of his band, a fusion of theoretical mathematics and ethnic cuisine.

“I think googleplex is the biggest number that we have a name for, and kugel is a traditional Jewish food,” he said. “There is an extravagance and largeness implied in the [invented] word that we find attractive.”

Self-styled as “cabaret meets old-world shtetl,” Kugelplex’s band of six will celebrate the release of their first album “Ceci n’est pas Klezmer” — French for “This Isn’t Klezmer” — with an unconventional performance and party that will include belly dancing, dreidels and a piñata Sunday, Dec. 12, at Amnesia in San Francisco.

“What’s great about this music,” says Reich about Kugleplex’s merging of klezmer with other musical genres, “is that throughout its history it has incorporated secular elements, along with Gypsy, swing and jazz traditions, picking up on the residue of other cultures. Musicians are like that. This is how a common ground is reached.”

David Rosenfeld, who plays the mandolin and fiddle in the band, says that Kugelplex is about introducing improvisation to tradition.

“We start with melodies hundreds or even thousands of years old that were passed through oral and written traditions, and we bring a contemporary jazz improvisation sensibility,” Rosenfeld, who is from the Bay Area, explains.

“We use spontaneity and in the moment communication to take music to new surprising places. We bring a sense of humor to the music.”

Both Rosenfeld and Reich agree that humor often coincides with surprises.

“When we’re hanging out jokes and puns and witticisms are just flying around,” says Reich. “There’s a similar kind of interaction when we play music. There’s a phonetic energy to klezmer that often sounds humorous and we try to exploit that to the fullest.”

Rosenfeld explains that through member changes in the band, improvisation occurred naturally.

“Improvisation is a part of musical beings,” says Rosenfeld. “Sometimes when we are performing we don’t know what’s going to happen at the end of a song. We use subtle communication and eye contact to come up with an ending that makes sense.”

For an example, Reich cites “Another Glass of Wine,” a track on the album that he says best represents their sound.

“It is a rousing number,” he explains. “When people think we can’t go any longer we just keep on playing.”

When Reich first became interested in klezmer as a student at Oberlin College in Ohio, he realized that the songs and the melodies already had a place in his memory and imagination. Reich, who was raised Roman Catholic (but recently found out he had a Jewish grandmother), was drawn to the music.

As a 13-year-old living on Long Island, Reich went to a bar mitzvah every few weeks. He can’t recall his middle school reaction to the traditional Jewish music interspersed between sets of ’80s pop, and he doesn’t think he ever saw a live klezmer band.

But something about the music stuck with him. Now 13 years later, he is a professional klezmer musician and teacher playing with Kugelplex at venues around the Bay Area from Saul’s in Berkeley to private bar mitzvahs.

“We’ve played at a couple of great bar mitzvahs, where kids were break dancing to us playing klezmer,” says Reich.

Kugelplex will perform at 9 p.m. Sunday, Dec. 12, at Amnesia, 853 Valencia St., S.F. Tickets: $7 to $15 (with CD). Information: www.kugelplex.com.