Classtools.net is a free flash tool website that allows you to create quizzes, diagrams, and educational games. You can then host them on your own site free of charge.
You can sign up for the premium version of the website if you want access to more tools or ad-free templates.
If you're looking for a fast and responsive mind mapping tool for your students to use when they plan a project or diagram a concept, give Slatebox a try. Or if you just want to create organization templates for your students to use offline, you can use Slatebox for that too. Create your template, download it as an image, and print it out.