RPG characters don't throw parties very often. In fact, I can personally count the number of times PCs have attended an actual organised party in a game I've been involved in on the fingers of no hands.

Which is a bit of a shame, because a party is a great social occasion during which PCs can mix with dozens of people, making contacts, hearing gossip and rumours, and trying to keep an eye on the various VIPs, allies, suspected enemies, and other assorted hangers-on. And because of the number of people, a party is a great opportunity for a villain to make a splashy show with some sort of attack or abduction.

If you're blessed with heroes who have secret identities as wealthy society types (think not just Batman, but also the Scarlet Pimpernel and Zorro), naturally they should attend high class parties. And when their alter-ego is inevitably required to perform some heroic act during the party, things can definitely get interesting.

Transcript

GM: The Ewocs throw a big party to celebrate Han and Princess's nuptials.
[SFX]: {musical notes}
Lando: Han! Congratulations!
Han: Lando!
Han: Good work destroying the Peace Moon! Sorry we couldn't be there. We ran out of explosives.
Lando: Right. Say, where are you all going after this shindig? I'll offer you a lift in the Falcon.
Han: We should finally check out the Dagger Bar.
Chewbacca: Raise a glass of tuna booze oil for Jar Jar?
Leia: No.
Han: Great idea!
Leia: We're going on a honeymoon.
Han: To the Dagger Bar?