My grandparents and their nice old lady neighbor have a deal - whenever the old lady gets up in the morning, she will light a candle (that's how old she is :D) and my grandparents will respond with a light in their window that they have seen it. So I thought to myself, why not tap into the light and add a little ESP8266 that automatically pings a server once it's turned on. Nice project for when I'm there the next time.