There are plenty of fun things you can do with a 3D printer, especially if you know a thing or two about Arduino, Raspberry Pi, and electronics in general. Take this GlaDOS ceiling lamp: it is a 3D printable motorized ceiling lamp that should look familiar to Portal fans. As you can see in the below video, this robotic arm lamp moves around and looks quite awesome:
You are going to need servo motors, basic tools, a soldering iron, a power source, and a bunch of other things to make this. Completing this project is going to take a while. The good news is you can find the files and instructions on Instructables and YTEC.