I used to use a really nice, simple, browser-based timing diagram editor, and now I've forgotten the name and URL of this tool. Does anybody know which one I'm talking about? There was a text window to enter signal names and values as strings of text, like 10xz01C00, and then the waveforms would show up on the web page. You could save a diagram and get the URL so you could use the URL to retrieve it. I think it was something written by some guy in his spare time.
Another nice thing I'd like is a tool to generate ASCII-art timing diagrams that I could insert into my code. They're a bit of a pain to draw directly.