My two business partners and I (we're 22, 22, and 21) created an invention that we started to sell earlier this year, called the Wrizz. We made it from scratch in my spare bedroom! You can view the website at
Wrizz.com. It was a long challenge, but it is fun looking back at what we learned. Basically, in the simplest way I can describe it, it is a mouse enhancement originally designed for computer gamers, but we are now focusing the attention to its ergonomic nature. It sits under your hand and elevates your wrist, and is quite comfy! Although we haven't sold a ton or made a fortune off of it, I am impressed that we turned just a drawing on a piece of paper into a tangible item! We literally had no idea what we were doing at first. Here is a quick pic (more on the website):
