Made of an old plastic bucket.
Exactly what it says on the tin: a remote-controlled robot built to look like R2D2. As time went on, I did add some more advanced features, such as text-to-speech and video streaming.
This was made for several occasions: the STEM fair, and Halloween later that year when I went trick-or-treating as Luke Skywalker.
I started with the guts of an earlier robot I had built: two Lego NXT motors, connected to a Raspberry Pi through an H-Bridge motor driver. I spent a lot of time adding features to this robot: it could be controlled using a Wii remote, a smartphone app, or an interactive website. It had speech synthesis software and an internal speaker, a camera mounted to allow video streaming, and a few LEDs for blinkenlights.
By the end of the project, I had switched to using an NXT brain to control the motors, connected over USB to the Raspberry Pi.
It did its job and did it well. This project was one of the first significant software projects I worked on, and it taught me how to design and organize a program longer than just a few lines.