I would like to know what your hoppy coding project are. It doesn’t really have to serve a purpose, but what are you coding on in your free time that just is fun to you and you enjoy working on?

As a background: I am an experienced programmer and do earn my money with it. In my free time I always enjoyed trying out new stuff related to technology, learn new things and improve my skills by doing so. But lately I recognise that I just have no clue what I should do or what a fun toy project I could work on. I really have no ideas. My head just feels completely empty whenever I open my IDE.

So please, tell me what you are coding on for fun.