"Six Degrees of Kevin Bacon" is a popular game based on the idea that any actor can be connected to Kevin Bacon through a chain of co-starring roles in films. The concept is rooted in the broader theory of "six degrees of separation," which suggests that any two people in the world are six or fewer social connections apart. Players typically start with an actor and try to link them to Kevin Bacon by naming films in which they appeared with other actors, ultimately connecting back to him. The game highlights the interconnectedness of the film industry and has become a cultural phenomenon, inspiring various adaptations and discussions about networking.