I got the kids involved in building models out of junk with me one weekend.
Here's the model I worked on myself...first a few finished shots...
Kinda reminds me of a Matrix vehicle.
Here are some pre-paint shots...
Hot glue, plastic bits, a container from the recycling bin, and spray paint. This one turned out pretty nice after painting...but it looks much better in person than in my photos. Flash highlights all the imperfections.
What I learned from this project was that it's useful to mount your base piece (in this case, a lemon juice container) on some kind of stand to start with, and that hot glue leaves lots of spiderweb-like strands that are super annoying.
This project was quick and satisfying. It's kind of impressionistic and didn't require any planning. Now, if you wanted clean joints and precise details, then you'd have to work in a much more precise way.