Hmmm...how about an exciting scavenger hunt around the neighbourhood? Or maybe setting up a tiny picnic at the local park? You could also plan a nature walk and do some basic bird watching or go on a fun insect-catching adventure (with the commitment to release them back into nature after, of course).
For indoor days, I'd suggest having a little art exhibition at home! Encourage your child to create an artwork or two inspired by their favourite things. It could be anything - favourite cartoon character, animal, or even an imaginative scene they've created. Hang their masterpieces on the walls for a fun little exhibit and host a mock opening ceremony! Why not invite some of their friends over to join in the fun and make it into a mini art party?
If you're up for a bit of prep work, you could also plan a themed day centered around your child's current obsessions - pirates, space exploration, or even a favourite colour! Go wild with decorations, food, games and activities all sticking to one exciting theme.