Ask HN: What are your favourite founding stories of startups?

I really enjoy reading about founding stories of startups. It's surprising how some of the most successful companies started out with something minimal when they were a startup.

My favourite is the founding story of WhatsApp. Jan and Brian launched WhatsApp with just one feature: the ability for users to set a status. It failed horribly. However, they didn't give up and paid close attention to the users. They noticed that users where setting statuses that indicated that they wanted to message to people in their contact book. So the founders iterated to instant messaging and launched again and it took off!

What are your favourite founding stories of startups?