On Monday night around the fountain at Lincoln Center, two kinds of gowns flooded the plaza in a whirling mass: purple choir gowns, worn by graduating students of New York University, and pricey designer gowns, worn by patrons of the American Ballet Theater, arriving at the Metropolitan Opera House.

“I like my gown,” said Samantha Winer, who had just graduated from the N.Y.U. Silver School of Social Work.

“But you’re more interested in doing good than being rich,” her grandmother told her.

Who says you can’t do both? After all, this is a city that would be in big trouble without the blood sport it calls fund-raising.

And the American Ballet Theater wasn’t messing around with its 75th anniversary jubilee celebration. From the balcony of the opera house, women in gowns to rival the architecture looked down as more than 1,000 guests arrived.