A skit is a funny or informative short play. It's usually more fun to perform a skit about an alien invasion than a skit about workplace safety.
You might watch a skit about bullying at school, and the local theater troupe may perform skits in the park for kids. In stand-up or improvisational comedy, skits are more commonly called "sketches." Skit comes from the now-obsolete Scottish skit, "a vain, frivolous, or wanton girl," which became "a satirical remark" in English, and then "a piece of light satire."