Now that summer is here, the good/bad news is that kids will have a whole lot more unstructured time on their (and likely, your) hands. When they can't be outside, it helps to carve out some space in your home where they can draw, build, and craft their way out of boredom.
A small table and chairs will do the trick, just make sure you can wipe it down easily (we love Sprout for their durable, sustainable, affordable kids furniture, also Ikea always has great options). It's handy to use cups to hold markers, crayons, paint brushes and the like, so that kids can easily put them away. We like to use drawer organizers to store larger things like construction paper, clay, stamps, beads, and other craft items. Then do larger bins to contain their completed "masterpieces".
Once they have that space to create happily on their own, just sit back and enjoy all the peace and quiet! Just remember to tell them that slime, glitter and play doh potions maybe shouldn't go down your powder room sink (don't ask how I know this). Happy summer!