Cool 404 page

Right now, we're sending all 404s to the home page with no indication that nothing exists. We shouldn't do that. We can have some fun on this page _and_ suggest something to visit instead.

I've linked up some recent content and silly words. What else can we do?

### Ideas

* http://www.webdesignerdepot.com/2013/05/15-really-creative-404-pages/

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