How to Smile is a great place for teachers to find ideas and directions for hands-on math, science, and engineering lessons. How to Smile is community site to which teachers can contribute their lessons and materials for others to use. You can search for lessons by keyword or by browsing the popular activities lists. Registered users can bookmark materials within How to Smile. How to Smile has a free iPhone app that you can use to search for lessons.
Applications for Educators:
Whether you're looking for a brand new lesson plan or are just looking for some ideas to tweak your existing lessons, How to Smile could be a great resource for you. From what I saw by browsing the lessons, it appears that the majority of the lessons are geared toward the K-8 audience.