Okay kiddo, have you ever played make-believe with your friends? Well, actual play is just like that, but with grown-ups who play pretend games called tabletop role-playing games.
They sit around a table or video call and take turns telling a story together. One person is the game master and sets up the world and characters, and the others create their own characters to play as.
They use dice and rules to decide if their characters succeed or fail at the things they try to do in the story. They have to work together and use their imaginations to solve problems and complete quests.
It's like being in a play, but they make up the story as they go along and everyone gets to be part of it. It can be lots of fun and a great way for friends to spend time together telling stories and having adventures.