While perusing the web this morning, I found this very nice, simple
AJAX HTML editor. Very simple in its design and implementation, I find that I can't stop playing with it (hey, mind out of the gutters!).
Often, while developing sites or working on projects, I will work on some HTML trying to come up with either a layout or new style. Either way, I usually create a quick test page, edit my code, and refresh the page in a browser while tweaking. With this real-time editor, I can see my results as I type. Simple but very effective.
So go ahead, try it out... that's right, play with it for a little while but stop if it starts to chafe.