Everybody knows the game "6 Degrees of Kevin Bacon." Someone names an actor or actress and you have to tie that person back to Kevin Bacon.
For example, Selena Gomez. You wouldn't think you could tie her to Kevin Bacon, but you can! She and Mary-Louise Parker were in Behaving Badly together and Mary-Louise Parker and Kevin Bacon were in R.I.P.D together. So, Selena Gomez has the Bacon number of 2 because there are only 2 degrees between her and Kevin Bacon.
This game is seriously addictive and requires pretty extensive movie knowledge, but there is an awesome cheat you probably never knew about. You can calculate the 6 Degrees of Kevin Bacon Number of any celebrity by simply Googling their name + Bacon Number. The number will come up and how you get it. Warning, once you do this, it gets a little addictive. Also, it's hard to find a celebrity with a number higher than 2! (BuzzFeed)