Is it a big party where everyone on the planet is in on it?
Making everyone a pirate?
A party on the moon?
Everyone has so many theories but never seen anything concrete.
Delivering binks sake?
Having a giant sleepover where everyone tells their dream? (Since apparently the one piece is a giant pillow)
I think becoming king of the pirates is something Luffy think he needs to achieve in order to make is dream a reality