I found a hilarious example of security through obscurity on a doctors' office web site today. I right clicked a link so I could do Open in New Window, but some javascript caught my right-click and popped this up instead:

Not only does this annoy users and look unprofessional, but it protects nothing! You could click View -> Source or open the files from the IE cache if you really wanted to copy some code. I can't even figure out what they think they're protecting since the majority of the javascript on the page is just for popping up that annoying message box.

I was curious to see what kind of web development outfit would use such ridiculous security measures, so I clicked their link at the bottom of the page. I laughed out loud when I saw their web server had apparently been protected about as well as their HTML. Hackers had replaced their homepage with the following message:

I'm still chuckling about this one.