WHITE TIE

You must have fancy friends, because this dress code isn’t capital-f formal—it’s all-caps formal. If you don’t want to invest in a ritzy (a.k.a. expensive) gown you’ll likely wear only once, you can rent one. The Canadian company Rent Frock Repeat has a huge inventory (more than 1,600 dresses) of stunning silhouettes in sizes 0 to 24. Badgley Mischka sequined gown (sizes 12 to 16), $170 (for a four-day rental), rentfrockrepeat.com.