Can I borrow that box? I need to do an Instructable?
Yes, #2 son has done an Instructable. He's only six, so be nice. (ahem) It's his first Instructable...
Step 1: What You Need.
You need a big box, a big pen, a big pair of scissors, and the last of Daddy's duct tape.
Step 2: Get It Ready
Stick the flaps together with the duct tap to make the box taller.
Draw the crenellations and door.
Step 3: Cutting the Crenels.
Crenellations are important. It's not a castle if it doesn't have crenellations.
Did you know that the crenels are the gaps, not the sticky-up bits?
#2 son found it easier to cut all the vertical cuts first, then bend bits over to cut them off.
Step 4: The Door.
#2 son decided I should use my Instructables knife to cut the door.
Holes got poked so he can pull the doors shut from inside.
Lumps of card duct-taped to the inside of the doors made slots to put a bar across the doors.
Step 5: That's It!
For now, the castle is finished, but #2 Son has plans - he's thinking about painting it to be more realistic (real castles are painted white inside), and is keeping his eye out for more card to make a drawbridge...