Wonder Woman planned a Team Bonding Day for the League and all its affiliates (aka Batman Inc.)
Everyone gaped and stared as Gotham's Wayne family strode onto a public beach (public, the atrocity, Bruce harrumphed.) accompanied by a large group of people that all looked like they belonged on the front page of Vogue.
Literally everybody was ridiculously ripped. The sheer unfairness of it all.
All the other civilians quieted as the group walked past, cowed by their intimidating aura.
That was broken, however, when Dick Grayson whooped and did twenty consecutive backflips into the ocean.
Everything descended into chaos after that.
Marinette Dupain-Cheng took off the t-shirt she had on top of her swimsuit, revealing the black two-piece swimsuit with a red bat emblazoned on her chest, making Jason Todd-Wayne turn the same shade as the bat.
Diana Prince challenged Clark Kent to a beach volleyball match. Clark managed to convince Bruce Wayne to play on his side, and since no powers were allowed (if the beach was private, they wouldn't have this problem, Bruce groused.), the Bats playing had a large advantage. Diana had Cass and Damian on her side, while Clark had snagged Bruce and Dick. Marinette refereed. She was barred from playing, as she couldn't turn off the luck she got from using Tikki.
In the end, nobody won. Clark bumped the ball with a little too much strength, sending it flying off into the horizon, lost for good.
Tim Drake-Wayne put down a lounge chair and promptly fell asleep, not even remembering to put on his sunscreen. Jason had the brilliant (read: stupid) idea to write a message on Tim's exposed chest in sunscreen, so that his extremely pale skin would burn around it. Marinette tried to talk him out of it, but it didn't go well.
Tim woke up three hours later lobster red, except for the words Jason wuz here on his chest, which were his usual pale shade. He immediately started planning his revenge on Jason, but it wouldn't happen today.
Everybody got into one massive water fight, sans Tim because he was still sleeping, and Jason and Marinette. Nobody knew where they went.
Cass found them an hour later, making out in a tent they set up that nobody even knew they brought.
She dragged them back to the main group, where they were spread out on a massive blanket eating Alfred's amazing cooking for lunch.
Everyone then teamed up to build a massive sand fortress, large enough to hold three people (and using all the sand in the vicinity) complete with a moat, and many snapped pictures of their work until Dick did one too many somersaults and crashed into one of the walls.
Surprisingly, the League's building skills held stronger than his nose.
When the sun started to set (yes, they spent a whole day on the beach, there was a lot to do), the couples paired off and found their own space to admire the beautiful sky.
Jason and Marinette went back to their tent, only to find it... occupied by Bruce and Clark. They left very quickly to find another spot.