It was after 9 p.m. on a recent Wednesday inside the atrium of a sleek glass office building in Midtown Manhattan, and Jacky Yu let out a scream.

She and six other people were playing One Night Ultimate Werewolf — a card game in which players have secret roles and use deduction skills to discover each other’s hidden identities — and there had just been a big reveal.

“We got really excited,” Ms. Yu, 31, said.

The room was buzzing. Hundreds of people had gathered for an evening of game playing. Every table was occupied by clusters of people leaning in, laughing and competing.

New York can be expensive, overwhelming and intimidating, and sometimes it is hard for people to connect. A martini can cost $25 in a bar that’s too noisy for conversation, and raucous nightclubs aren’t for everyone. So a free, monthly B.Y.O.B. (bring your own board game) night in an office building food court has become a big hit.

In addition to Werewolf, people were playing classics, like chess and mahjong, but also relatively newer games, including Catan, Splendor, Hues and Clues, Saboteur, Nertz, Wavelength, Blokus and Camel Up.