I just tried to explain your 3-06-04 post to my 6 year old son, who started asking me questions that went into the realm of quantum physics. Where does light come from? What is it made of? How does it get here? Personally, I'm thrilled he's interested. The picture really got him going!
But the definiton of a photon being: "a quantum unit of electromagnetic radiation or light energy; an elementary particle that is its own antiparticle" doesn't translate well.
Those little eyes got big, fast... LOL!