Atlas Improv Company

The venerable comedians-without-a-net of Atlas Improv celebrate 19 years with 19 hours of laughs during the return of Endurance Fest. “Panic Room” warms up the stage at 7 p.m., March 23, with a mix of stand-up and improv featuring Alecia Altstaetter, Josh Glen and Vanessa Tortolano. The main event is an improv free-for-all with performers from around the U.S. on Friday (7 p.m.-midnight) and Saturday (1 p.m.-2 a.m.). Admission is free all weekend