3DVinci's SketchUp page has some very good resource for mathematics teachers, particularly Geometry teachers. 3DVinci presents a collection of mathematics projects that students can do using Google SketchUp. If you've never used SketchUp, don't worry. 3DVinci hosts video tutorials that will show you everything you need to know to get started using Google SketchUp to teach mathematics.
Applications for Education
3DVinci's SketchUp projects could be a good resource for teachers who are looking for lesson ideas that will get their students to think about mathematics in a way that isn't just numbers and equations on paper (virtual or physical).