I have a Notebook and a Evernote notebook about this. I write down all my ideas on these notebooks. My passion is so big about startups, that sometimes I do this when I have a Patient. I stop the treatment and with the help of my nurses I write the ideas on the list.

But the ideas are not revolutionary. It seems that everything is already done. I know that always there is a unsolved problem but, I don't know if it's my fault or it's normal, it's too hard to come up with a great idea nowadays.