You can go up to any extent of registering a domain when URLs are coming quite affordably in your way and here is an example which is nothing but a landing page to tell you, how DEFINITELY is spelled :P.
One more in that list is – www.wwwdotcom.com which says like –
You have reached the very last page of the Internet.
We hope you have enjoyed your browsing.
Now turn off your computer and go outside.