Training wheel (yes just 1!)

To this day I remember* riding my bike with my dad along a busy road and my training wheel fell off, and I fell in to the street. No damage was done, but we had to ride the rest of the way home with my dad holding on to one of my handlebars so I didn't fall over.

Now, if I only had this wheel. It's a replacement front wheel with a built-in gyroscope that keeps the wheel stable and upright. Awesome...



*At least I think I remember. I was 4. :)