While writing up a proposal for how a docs site should work, I found myself trying to create an example as part of a presentation. My presentations skills probably are not as good as yours, but the result was ugly. So ugly in fact that it prevented me from expressing what I needed to say.
Yesterday I ran across Balsamiq Mockups, and watched the demo video. Looked easy enough.
Today I tried it. Even though I’m probably the last person on earth who should be allowed near UI design, I was able quickly with the web-based demo to come up with an example that says what I want and does not look half bad.
Impressively usable software!