Having seen the quantity of restaurants in Paris without an online presence, I developed a system to quickly generate static websites for small businesses, with the intention of generating some additional income. Unfortunately sales does not come naturally to me so I never gained any clients, but I learned a reasonable amount about business development in this time. The video below goes into some technical details of the system, which I have in fact used to deploy this very website.
Also while living in Paris, I coded a website that allowed me to see details of the exit maps of Metro stations. This was for my own personal use, and as I could not source the data needed in bulk, pictures only exist for stations where I took a photo of the physical map to refer back to later.
When the official website for displaying fixtures and tables for my hockey club was not mobile friendly, I wrote a simple skin that scraped the data and displayed it in a responsive format.