I am named after my grandfather, Joseph Friday. The name is actually Belgian in origin, and it was anglicized to “Friday” from “Vendredi”.
As I always say, my grandfather, after whom I'm named, had the good sense to die before the Dragnet TV show came on, so he didn't have to face a lifetime of jokes. But if my cellphone were to ring right now, you would hear the Dragnet theme song, so it's something I have a great deal of fun with.