Jesse James and Frank James
The James brothers, members of the infamous James-Younger Gang, are my 9th cousins 4 times removed on my father's side (via the Beasley family). It is possible that some of my Missouri relatives were knew the James brothers, perhaps from the other end of their guns. The James-Younger Gang was known for terrorizing the area of Missouri where my family lived.
My wife's family has a story that her great-grandfather, a very secretive man whose origins are unknown, was once a member of the James-Younger gang. If he was, it was under a completely different name, which I suppose is not that unlikely. Still, I doubt this story is true.
Likelihood of relationship: 50%