This is the omath demonstration applet. If it doesn't seem to be working (you don't see an 'In[1] :=' prompt below), it's probably because you don't have a Java 1.5 runtime, or it's not configured to work with your browser. You can download the latest Java runtime here. You'll probably notice that the load time is quite bad; we know how to fix this: serializing the initial KernelState, rather than building it from scratch.