Perhaps the only thing cooler than building stuff out of LEGO is building a submarine out of LEGO.
That’s exactly what Captain Greybeard did. LEGOs don’t have a real problem going underwater, but the electronics in the Mindstorms NXT kit sure do. The Grey November solves this problem in a low-tech way: by using a plastic bag.
Here’s a video of the sub cruising around in a swimming pool. It even includes an underwater view:
Special thanks to MAKE for finding this cool project.