Comment by knowtheory

It looks like they're serving off something called "rc":

   $ curl -I harmful.cat-v.org
   HTTP/1.1 200 OK
   Content-Type: text/html
   Server: rc-httpd
   Connection: close

It is ironically listed in the "Less harmful alternatives" and links to a page hosted on itself: http://rc.cat-v.org/

Edit:

Sorry my bad, `rc` appears to be part of Plan9 (see: http://webcache.googleusercontent.com/search?q=cache:Mc7xQBU... ).

Here's the cache link to rc-httpd which seems to be the thing that's buckling under the load:

http://webcache.googleusercontent.com/search?q=cache:3ahE0vd...