Billy Day is a holiday that happens on the 18th of every month. On this day, every living creature is named Billy. No last names, no middle names; everyone's full name is Billy. Why is this, you may ask? Life gets a bit more interesting when you can't just use a shortcut (like someone's name) to refer to whom you're talking to/about. You'll have to do what you can to make it clear to people which "Billy" you're referring to when you say "Billy."
It's been asked before, "What about someone whose name is already Billy?" Their name is still Billy on Billy Day.

A man who's cultural impact was not realized until he passed away. Possibly the only man in the world who could pump himself up about useless products that he probably didn't even use.

The first man on Earth to ever speak IN ALL CAPS.

R.I.P.

Billy Bum; a bum named Billy. Equivalent of a human skid mark. Plural: Bums of Billies

A group of retards in a shopping mall.

A couple in which the girl and guy are both athletic and perfect for eachother. They are envied by many of their friends.

Licking your finger and sticking it in someones belly button.

Boring ass 90 year old Greek Mathematician whose actual name isn't even billy.