Friends and lovers: “Insignificant Others,” L. Jay Kuo’s musical play, presents the romantic stories of five Midwestern friends — two gay men and three straight women — who have moved to S.F. [8 p.m., Zeum, 221 Fourth St.]

Who’s in town

San Francisco native and popular balladeer Johnny Mathis performs with the San Francisco Symphony. The concert is part of the symphony’s Summer in the City festival. [8 p.m., Davies Symphony Hall, 201 Van Ness Ave.]

City activities

All about Mozart: The Midsummer Mozart Festival performs music by the composer. George Cleve conducts the festival orchestra. [8 p.m., Herbst Theatre, 401 Van Ness Ave.]

Art social: The Mission Cultural Center for Latino Arts hosts an opening reception for its 30th anniversary art exhibit and sale. Works by 50 local artists are on view. [7 to 10 p.m., Mission Cultural Center, 2868 Mission St.]

Literary events

Poetry fundraiser: Robert Hass, Sharon Olds and Brenda Hillman, among others, read from their work. Proceeds benefit the Squaw Valley Community of Writers. [7:30 p.m., First Unitarian Universalist Center, 1187 Franklin St.]

Peter Charles Melman: The novelist discusses “Landsman.” [7 p.m., Books Inc., 601 Van Ness Ave.]

Lectures

Relations with Russia: Discussion features Russian and U.S. perspectives on the economic relationship between Russia, the United States and the rest of the world. [Noon, World Affairs Council, 312 Sutter St.]

Sex trafficking: Survivors, law-enforcement voices, activists and researchers discuss sex trafficking in San Francisco. Girl Fest presents the event. [4 to 6 p.m., Sanchez Elementary School, 325 Sanchez St.]

At the public library

Magic show: Magician Brian Scott presents “Twisting Reality,” for ages 3 and older. [4 p.m., Merced Branch, 155 Winston Dr.]

‘Teen Gaming Day’: Event features video game equipment and games, including Guitar Hero, DDR and Wii. [2 to 5 p.m., Anza Branch, 550 37th Ave.]