I definitely would recommend the Hillwood Estate if your family is into decorative arts. It’s absolutely gorgeous.

There should be a few new exhibits in DC around that time including an afrofuturism one at the National Museum of African American History & Culture. Also, the bird house at the zoo will be open—but you will need tickets. There’s a Disney-themed exhibit that will be opening at the American History Museum.

For festivals, besides those mentioned there will be the Georgetown French Market at the end of the month.

The Kennedy Center is having a river themed festival — there’s one performer that makes instruments out of ICE https://www.kennedy-center.org/whats-on/festivals-series/riverrun/

If they enjoy art, I’d recommend going to the Phillips collection. If you can swing tickets, the Glenstone is always a treat too.