On math night at our school, my daughter's teacher gave my 3rd grader and my preschooler a Geoboard.  This was so thoughtful, and the kids love them, but I would like to know ways to teach with it.  

I've found a couple of sites about the Geoboard, but I would really like some advice from a teacher who has used it in the classroom and how to use it in both age ranges.

Thanks in advance for any suggestions that you may have!