I also have one tied to a manufacturing database at my company. When a batch of products rolls off the line I get an updated count of units made. Kind of a way to know production systems are running and there are no problems at the work cells.

I also made a rickety-ass system that scrapes the local commuter rail API and fires off a notification when one of my trains is late or cancelled. That's been pretty helpful. The rail company has a Twitter account, but I don't go there anymore. So I rolled my own.

ntfy makes this all incredibly easy. I love it.