Among the many amazing, fantastical things common to LEGO conventions, the Great Ball Contraption is a standout. It is essentially a Rube-Goldberg-esque machine that exists solely to justify its own existence. We’ve written about the Great Ball Contraption (GBC) a few times here, and most recently Ronald wrote a great walkthrough of how to get started building your own module. Ever since my first LEGO convention, I knew I wanted to build a GBC module. When our kids were old enough to attend a convention, they were similarly bitten by the GBC bug. Last year, for Christmas, I told my son that if he worked with me to build a GBC module, I’d pay for the parts to build it and a trip up to Seattle so we could enter it into BrickCon’s 2024 Great Ball Contraption. He was on board so we got to work. Design or Borrow a GBC? First,...








