When I was a wee one my parents always said I was going to grow up to be an engineer because of all the experiements and contraptions I made. I'm sure I made a lot of pointless things, but only the biggest failures I remember.
I can't remember exactly when this was, but I was probably 4 or 5 at the time. I was living in Florida and it was hot as hell and I really wanted a Slip 'N Slide. I needed a Slip 'N Slide. It was at this point I decided to make my own.
I examined our mildly steep driveway and determined it would be perfect for me to build a Slip 'N Slide of my own. I went and took every towel in the house; bath towel, beach towel, whatever. It was a household of seven people at the time, so there were a lot of towels to be found. I layed all the towels down in a line, and proceeded to soak them with the garden hose.
I felt my engineering marvel was complete and it was time for a test run. Upon the maiden run of my newly constructed Slip 'N Slide, I discovered towels probably aren't the best surface for sliding on.
I imagine someone came home to a driveway full of dirty wet towels, but by then I was probably hard at work on my next project.