It's a phrase used to indicate something that is enjoyable, entertaining, or exciting.
Here are some examples:
* "¿Qué quieres hacer hoy? Quiero hacer algo divertido." (What do you want to do today? I want to do something fun.)
* "Hay algo divertido para todos en este parque." (There is something fun for everyone in this park.)
* "Vamos a buscar algo divertido para hacer." (Let's find something fun to do.)