I lucked out and ran across AppInventor 2 from MIT (it was once owned by Google) and it looked pretty cool, so I started trying it out. The very first tutorial was enough to get me wound up. Over several days, I experimented and coaxed an app out of it and then went totally nuts. It's still a work in progress like all my projects, but it is SO COOL!
Here's the screen you see when you first tap on it