Perhaps you've heard of Six Degrees of Kevin Bacon? Well the game works equally as well for genealogy. Kevin Bacon is my 11th cousin thrice removed on my father's side (via the Beasley family). Our common ancestor is Thomas Morgan, Lord of Castell-Arnallt, born about 1534 in Llanrhymny, Monmouthshire, Wales.
Likelihood of relationship: 40% for me.
While it may take up to six steps to connect anyone to Kevin Bacon through movie credits, scientists believe it may take only one or two steps to do it genetically. On the PBS show Finding Your Roots scientists at 23andMe.com used DNA evidence to show that all the celebrity participants (which included Kevin Bacon) linked to each other through only one or two relatives.
Fun fact: If you type an actor's name in to Google and follow it with "Bacon Number", Google will tell you how many degrees of movie separate the person is from Kevin Bacon.