From Family Room Forts to Big City Skyscrapers … Crazy Forts is a Great Choice to Encourage Design and Building Here’s a paid DIY STEM activity that’s tons of fun and engages kids in engineering thinking and design. At 22 / 25 points, the rating is Buy IT or Borrow It! Crazy Forts is a great idea for a present for any occasion. You can add on components so the building creativity is almost endless. Great activity to build confidence and curiosity as a lot of trial and error.