ON a Sunday night last month at Daddy’s, a bar in Williamsburg, Brooklyn, more than a dozen people in their 20s and 30s gathered at a professional soiree, drinking frozen margaritas and nibbling store-bought cookies. With their thrift-store inspired clothes and abundant tattoos, they looked as if they could be filmmakers, Web designers, coffee shop purveyors or artists.

When talk turned to a dance party the group had recently given at a nearby restaurant, their profession became clearer.

“Did you try the special drinks?” Sarah Gentile, 29, asked Jennifer Yao, 31, referring to the colorfully named cocktails.

“I got the Joy of Sex,” Ms. Yao replied. “I thought for sure it was French Women Don’t Get Fat.”

Ms. Yao could be forgiven for being confused: the drink was numbered and the guests had to guess the name. “613.96 C,” said Ms. Yao, cryptically, then apologized: “Sorry if I talk in Dewey.”