Seeing your favourite singer perform, getting married, perhaps even the birth of your first child.
All of the above are usually contenders for the greatest day of people's lives. For Harry Potter fans though, we might just have a new champion.
As part of a new Wonder Years series celebrating the films we all grew up with, Dublin's Lighthouse Cinema has announced a Harry Potter sleepover, where all eight movies will be shown back to back throughout the night.
The event page lists the duration as 1,365 minutes (22.75 hours) so you'd want to make sure you're committed before getting your ticket. Oh, and fancy dress is encouraged, obvs.