Idea for a warm-up that helps build shared understanding of group's similarities and differences.
Set up is like Red Light/Green Light, with all players lined up at one end of the space and joker at the other end. The joker turns his back and calls out some identity or trait that people might share: for example, "Postal Workers" or "Single Parents" or "people who love John Legend", then says "`1, 2, 3" dragging it out or suddenly speeding it up, then turns and yells, "stop!" Repeat until some player reaches the joker.
So: "People who are union members. 1, 2, 3.... Stop!"