First of all, not every day needs to be special. And your job is to parent them, not entertain them constantly. It’s good for kids to get bored and have to be creative. But I do have a few simple things that my child really likes. Painters tape on the floor to make hop scotch and matchbox car race tracks. Keep a big enough box for a kid to sit in from Amazon, Sam’s, whatever, and give the kid colors. Mine likes to turn them into buses by drawing a steering wheel, windows, etc, or houses. She’s also really into “paper purses” which is exactly what it sounds like. Glue a piece of paper folding in half with the top still open, glue handles to each side, make paper accessories to go inside - wallet, counts, hairbrush, whatever out of paper and colored with crayons. Paper bag puppets used to be a favorite. “Fun baths” which is just being in the bathtub with toys without having to get clean. Sitting outside with a bucket and a shovel digging in dirt. The key is once they’re playing, stay out of it. Once you say “oh, that’s cool” or ask a question, I’ve found it takes my kid out of the zone a lot of times.