Photos from Flushing Meadows: Arthur Ashe Kids' Day

When the day was over, a rainbow greeted families as they passed the Unisphere outside the National Tennis Center.

Each day during the U.S. Open, we'll publish a photo gallery of on-site images from Anita Aguilar. Steve Tignor will provide the captions, but he's also looking for your best work. Can you beat his caption of the first photo? Write yours in the comments below and he'll announce the winner in tomorrow's gallery.

The stars were out again for Arthur Ashe Kids Day on Saturday. There was Rafa, there was Roger, there was Serena, and there was Michelle. As in, First Lady Michelle Obama, who attended with her daughters—and put Flushing Meadows on security lockdown for the day. Here’s our look at the festivities in New York.

Serena: “I know!” Rafa: “¿Yo no sé?”

Can you do better? Let Steve know in the comments below.

The woman affectionately known as FLOTUS—First Lady of the United States—came to celebrate U.S. tennis and promote her “Let’s Move!” exercise initiative. Here she is with Serena Williams and Jack Sock.

Later Mrs. Obama sat with Billie Jean King and the family of Arthur Ashe.

With the First Lady in the stands, tennis’s No. 1 player, and resident court jester, Novak Djokovic, took the stage.

Nole faced some stiff competition, including a leaping forehand from this young girl. Remember that shot, we might see it on this court again someday.

And maybe this fist-pump as well.

Afterward, Novak obliged by autographing pretty much every piece of clothing the kids were wearing.

There were tennis warriors all over the stadium on Saturday...

...as well as happy fans...

...and smiling legends. Wheelchair No. 1 David Wagner joined Rafa and Roger on the sidelines. Who was cracking them up?

That would be Serena Williams, who tried out her one-handed backhand.

With a low-five, Serena yielded the stage to Wagner.

Rafa and Roger, old rivals, found something to laugh about together. Hopefully it wasn’t the competition...

Serena celebrates, as Federer wonders where his lead in the day’s competition went.

Legends, and their microphones, unite.

When the day was over, a rainbow greeted families as they passed the Unisphere outside the National Tennis Center.