No doubt you've stumbled upon one or 100 of these in your life as an Internet-capable citizen of the world. More often than not, you just back out and continue about your day, not at all looking for porn. But sometimes a webmaster goes that extra mile to make a dead end a place worth visiting.
There are some witty individuals who program their 404 pages with "hilarious" versions of "file not found" in other languages like Klingon ("De'teywI' 'agh vonlu'"), C-3PO ("Let the Wookiee have his files!") and zombie ("Arrgrg 404 BrAiNs aAAArrggh No ggrrgrh page brAiNz heRe BrAAAAIIINNSSSS!").
And then there are those who take it to a whole other level. Here's a sampling of the best the web has to offer to those who get lost during their quest for enlightenment.