The can crusher is a perfect representation of my "Weekend Project" mentality. Instead of vegging out and playing video games over my (entire) weekend, I like to get a working prototype up for some problem that I'm trying to solve. When I built the can crusher, I was melting down soda cans for aluminum to use in my metal castings and needed the cans to take up less space in the crucible. So, I bought a pneumatic piston from Amazon, turned a head for it on the lathe, and welded up a frame to make a simple can crusher. It substantially improved my workflow, and was a lovely use of a few days off.