Squishy Circuits is project from the University of St. Thomas that provides lessons, materials, and video instructions for using salt dough and sugar dough to create parts of electric circuits. These materials seem like they would be appropriate for elementary circuit kits all the way up to high school and college electrical engineering courses.
My favorite part of this site is the inclusion of several clear and concise video clips that support a teacher in using the materials.. good stuff.
See the embedded TED Talk below where AnneMarie Thomas describes the circuits.
Science for All 