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Coffeehouses have been around for decades. They are non-profits run by a dedicated team of volunteers. There is typically a modest admission fee or donation collected in baskets, jars, or hats as you enter.
Most coffeehouses take place at community-owned buildings like libraries, churches and other houses of worship. In particular, Unitarian Universalist Churches across the country have a strong tradition of bringing the community together around great acoustic music. We're not talking just Christian music here - but traditional folk music as well as more contemporary singer/songwriters.