If you're lucky enough to catch a glimpse of cardboard's enemy list, you'll probably find water up near the top alongside cats and fire. The two just don't mix, which is why it's incredibly impressive that the folks at Signal Snowboards were able to make a surfboard out of cardboard that didn't disintegrate as soon as it touched the ocean.
The project is a follow-up to the company's cardboard snowboard from earlier in the year which was a marginal success given it actually survived a handful of runs. But thanks to a waterproof polyurethane coating on the surfboard's cardboard honeycomb core, and a thin layer of see-through fibreglass around the outside, it's actually able to easily withstand both the waves and the water.
Not only that, because the honeycomb core ends up being so stiff it can actually be sanded like a real foam surfboard, allowing it be shaped with proper hydrodynamic curves and contours so it even handles well on the water. And to think, the only thing you turned that fridge box into was a crappy castle for your kids. [Signal Snowboards]