Hosting my nephews for a sleepover taught me an important rule of home safety: if you leave something out, it becomes a toy. It does not matter what the object was designed to do. Flashlight? Toy. Tape measure? Toy. Cardboard box? Luxury condominium. Decorative pillow? Apparently sports equipment.
Children also possess a remarkable ability to find the one thing in a room you forgot existed. If it rolls, opens, flashes, makes noise or has a button, they will locate it before you finish saying, “Don't touch that.”
Then there is food. I briefly considered preparing something thoughtful and balanced. This was adorable. When hosting kids, ask what they actually like and stock accordingly. A sleepover is not the evening to introduce your personal interpretation of roasted vegetables.
So put away anything fragile, dangerous or important, provide plenty of approved entertainment, and buy the food they want.
They'll still play with the box.