Is to party.
All you need is some money, booze, people and loud music.
But that's just too easy. It's brainless. Anybody can do that.
If you want fulfillment, then do something more challenging. Find a passion and keep pushing yourself to become better at it. Travel to different countries and learn how different cultures. Or help somebody out.
None of these come with a hangover.
Ultimately, create an identity with interesting stories no one else can replace. A story that only says, "We got so fucked up last night" is not an interesting one.