I don't know about creative and brilliant, but I have observed first-hand that midlifers who play have more fun. Unfortunately, while play seems to come naturally to children and puppies, adults can forget how. So following are some ideas to help get us started. Or we can let the kids make up the game. You might want to make sure their weapons are equally pretend.
Writers get to make up stories all the time.
Some even get paid for it. You might use a story line from your childhood fantasies. Or enter a world you have imagined visiting as an adult. Most colleges offer courses in creative writing. Surprises Dr. Brown says that play should be spontaneous.