What did you build for yourself thats NOT for business/work/income/productivity/games - Fun and casual only

There is a lit of focus on people building practical tools for business, have an angle to earn money, do things for their work, lots of coding utilities, and productivity tools.

All that us great, but I wanted to hear about the app you built for yourself only that has no commercial use at all. It is just for your enjoyment and fun, setting aside games because that could be for others or grow into a business.

Also avoid productivity use cases, I want to hear about the thing that is just because, that is something you said I don’t care, I just want it to exists for me.

Bonus points for things that you build and you now use regularly.