PBS
Pbs Learning Media
PBS's source for teachers, covering all subject areas. This is a site that has so much wonderful information as well as interactive activities that you are sure to find something that would be useful in your classroom.
PBS
Pbs Teachers: Toothpicks and Transformations [Pdf]
Using calculators, students investigate quadratic functions using geometric toothpick designs in this lesson that with a review of transformations of quadratic functions, vertical and horizontal shifts, and stretches and shrinks.
PBS
Pbs Teachers: String Telephone
Discover how sound vibrations travel across a string by making a telephone from paper cups, string and paper clips.