The thing is, people are trained to skip error pages. What do you think would happen if you format it as parked domain page? It's not the users you'd perhaps think lowly of that have the most trained impulse to close error pages; it's the more technical users.

Here's a suggestion: format the page as if it was taken down by the government. Something like this: http://corecorina.files.wordpress.com/2011/04/rippoker.jpg