I like the Arduino for this reason. It was a lot more interesting than printing hello world to a screen. I would find little things I could do with the Arduino for random little things that I couldn't easily do with a pre-existing app on the phone or computer.

Also, before I started studying computer science, I liked the Unity Game engine as it was quick to implement something interesting and it was easy to find lessons and instructions online to develop in C# and the Unity engine.