Demonstration
I've put together an example of the code in action.
We haven't attempted to make Rhubarb compatible in all browsers yet, the example certainly works better in IE 6 than FireFox 1.5 , and for this development we were targeting only IE 5.5+ and FireFox 1+ only. We tend to use BrowserCam for browser compatibility testing. If you haven't used it I can say that for me at least I find it highly useful and happily recommend it. We haven't used it for this project yet though.
The example highlights several limitations of the basic Rhubarb implementation, some of which are simply in later stories not reached yet. For example, CSS styling of the participate form is not yet possible meaning the form is too wide in FireFox on my screen.
Enjoy.