This is an activity I really like. Asia Ward developed the idea for workshops to introduce simple LED circuits. A simple light source - LED, battery and a switch to turn it on and off. To make them you'll need some materials:
Recycled Tea boxes (the most common size but any tagboard package boxes will work its just that the tea boxes keep the size small and the material needs low)
Bright colored paper
Card stock, in different colors - also called cover stock or pasteboard, (make sure you have some dark colors )sheets and scraps
Cereal box cardboard sheets and scraps
Foam-core or Cardboard cut into little pieces about 1/4"x1/2" ( these will be used as spaces to create "grounds" fore, middle and back ground
colored acetate scraps
LED's - 8 and 10mm of different colors
3V button batteries
Battery holders or DIY versions of holders (small binder clips + foam-core scraps)
Thin solid core or stranded insulated wire
Some tools:
Scissors
x-acto knives