My January Project is up.
This is a straight-up geeky math project (geek being a complimetary term these days). You start by building a cone, then use SketchUp's Section Plane tool to create four different conic curves: circle, ellipse, hyperbola, parabola.
This project has a Teacher Version and a Student Version. If the students doing this project also know about curve equations, the Teacher Version has some info about verifying equations by getting various point coordinates.
I'm guessing this is definitely NOT something the SketchUp creators had in mind when they created SketchUp, but it's awesome for math-types!
If this sounds familiar, maybe it's because you've seen my video on this topic (which I see has gotten over 2,000 views!)
Anyone can design anything in 3D! www.3dvinci.net