This was potentially the first major robotics project I was a part of that wasn't for a class or competition. I (a freshman in high school with no real experience to speak off) joined a team attempting an ambitious project of building a large RC glider that could deliver a rover through the air.
We didn't quite finish…, but we learned a lot with what we did get done. It was time well spent, I think.
I learned about foam core building methods for RC planes, the basics of raspberry pi and robotics and coded my first ever control system using an XBOX controller.
I also documented the project and made my first large poster (we needed to present our project to the board that funded us)