Neuron Simulator

From MAKE Magazine:

The Children's Hospital Boston have created a fantastic 'virtual neuron' which allows you to explore the basics of neural transmission with an interactive flash demo. Strictly speaking, of course, it's designed for children, but it's remarkably good fun whatever your age. Once you've got the demo window up, the options at the top of the screen allow you to choose different demonstrations, and the text below explains what's happening.

Read the whole article