Since we're all offering Scratch-asides, I'll note Hopscotch: https://www.gethopscotch.com/ – it's very similar to scratch, but I found it far easier to use. With Scratch I often feel like programming is a task of fighting with tile management. I also like the stronger emphasis on events in Hopscotch.

The big downside is that it's only really usable on an iPad.