I liked the penisland link – thanks!
There’s a few others that jump to mind. These are all valid and live (I’ve just checked).
To buy plants in Mole Station, New South Wales – http://www.molestationnursery.com
To find out which agent represents a celebrity – http://www.whorepresents.com
Looking for a therapist? – http://www.therapistfinder.com
Visit Lake Tahoe – http://www.gotahoe.com
Quick, get me some artwork! – http://www.speedofart.com
A church in the US – http://www.cummingfirst.com (seems to have been abandoned now?)
The classic used to be Experts Exchange, but they’re hyphenated these days and the old expertsexchange.com seems to be a cybersquatter page. Similarly, Powergen Italia (was this ever real or is it an urban myth?)