Along with a friend, I made an app for getting team feedback after the team meetings. It was done in short span during holidays for a hackathon. Also submitted here. Got some feedback but not many sign ups. Since I am not good at marketing what I did, we dropped the idea.
Had some pivot plans to change it to be a customer feedback platform for folks who are always mobile and dependent on their calendars while meeting with their customers. Not much enthusiasm left, hence dropped.
https://news.ycombinator.com/item?id=8855648
Every now and then would see something and get inspiration to reignite this but didn't go back.