The United Nations has labeled 2012 the International Year of Cooperatives. It's a business model Austinites are intimately familiar with, whether we're talking groceries, bicycle maintenance or yoga studios.

Like those other co-ops, the Austin New Music Co-op was created to fill a not-for-profit gap in the marketplace. It's just that its mission has been to provide Austin with new "art music": sounds and experiences by respected but obscure composers, stuff that doesn't often see the light of day.

The NMC is celebrating its tenth anniversary this month with a two-night gig at the Mexican American Cultural Center.

Travis Weller, one of the group's founding members, sips on a beer at his wooden-floored house in East Austin, recalling their first concert.

"The co-op started as a sort of loose collection of people who would meet once a week," Weller says. They met, practiced, improvised and played their own music until they had enough material for a full concert.

NMC played at the now-defunct Ceremony Hall on Red River (across from Hancock Center), in a set that incorporated slide projectors (remember those?), a detail that seems to mark how quickly time has passed.

"I remember we had a great crowd," Weller says. "We didn't get enough chairs — some people had to sit on the floor."

It was an affirmation that this music — the kind that doesn't even make it onto classical radio, let alone commercial radio — had an audience, one outside the forty acres.

That became their pattern: tackling important but under-played works of the 20th century, and commissioning music from working composers and their own members.

"We don't have an artistic director," Weller says.

Weller figures that in the past 10 years, NMC has given birth to 75 new pieces of music. That's including the hugely popular Fusebox Festival collaboration with Ellen Fullman and her Long String Instrument at the Seaholm power plant, and a concert last December of music that took two nights to complete. "We rehearsed two years for that show!" Weller says.

For a group that operates by consensus, this level of organizational expertise might be NMC's most impressive evolution. NMC does its own commissioning, performing and booking.

For a small group with a non-hierarchical structure, the work they do is remarkable.

They're planning to make a record, and they're also exploring how to take their group to the next level, perhaps with a more permanent, more official role for their donors.

Membership has changed over the years — some have moved to New York or overseas, but new blood has flushed in — and their interests have changed. Some pieces of music that NMC once championed have become better known, so they've given way to newer pieces that need to be played.

Their newest member has just moved to Austin from Athens, Ga., Weller says. "And she's playing on the concert." She had already taken the minutes at her first meeting.

NMC's anniversary concert is a greatest hits show of sorts, taking some of their favorite material from the past 10 years, including from their first show.

Over two nights they'll play works by Morton Feldman, Arnold Dreyblatt, Alvin Lucier and Cornelius Cardew, as well as their own members. That will require 20 singers from the Texas Choral Consort. As usual, this is stuff that doesn't come around very often.

They'll also have memorabilia, pictures and some NMC-built instruments.

Weller has more to say about the anniversary concert, but our time is nearly up: His front door opens and musicians start to dribble in for that evening's rehearsal.