when rich people go once a year to a fundraiser for the Metropolitan Museum of Art's Costume in New York. It marks the grand opening of the Costume Institute's annual fashion exhibit.
girl: omg are you going to the met gala this year in your new gucci slides?
boy: no bitch I don't want to spend my time around white pretentious girls
is a giant event that occurs in the show "My Little Pony: Friendship is Magic". It is where certain ponies of high class are invited to a grand ball at the palace where they enjoy fine dining, music, etc. This is also a event where the ponies may be able to meet the Princess. The Grand Galloping Gala is also to be said as a event where every ponies dreams come true.
I must wash my mane to look nice at the Grand Galloping Gala.