Hey mcw,
saw that post already, I am still thinking about what to do to participate. As biochemist there is unfortunately less of the colourful, "magic" chemistry, and a lot "okay, I have put now this colourless liquid into another tube with colourless liquid, let's wait 4h and see what has happened - o yeah, three bands on a gel instead of 2!". ;)
There are still lots of fun with science around and its definitely not necessarily to be biochemistry related :) Just share science you feel facinating and try go one step further and i bet everyone will enjoy it too !!
No worry, I am not planning to do any colorful chemistry stuff for the science fair as a self challenge XDD