My dad did. I was the third of three and one year old when my dad started a business to manufacture a high-quality version of a (then) novel electric motor which he designed and patented. He and his partner built the company to about 50 employees and then sold the business to a large industrial conglomerate a few years later.

I'm now 36, happily married with three kids of my own. I'm bgeinning something along the 37 Signals route - 10 hours a week until I have critical mass.

Overall, I must grudgingly admit that youth has the advantage, so I think us oldsters have to leverage the advantages we do have - experience, money and connections.