Well, once upon a time Michael Mandiberg, one of the chief Wikipedia contributors, decided: I will print it one day. And „when I started, I wondered: What if I took this new thing and made it into that old thing?“
Lulu.com is a website which is going to be used for publishing. It is developed to create and self-publish your books. Web Wikipedia (a compressed one) weighs 11 GB and it's a question of about two weeks to upload it.
As soon as the process if finished, be ready to pay $500,000 to obtain 7,600 volumes of the free encyclopedia or $80 per each one. As for pages, there will be 5,244,111 of them altogether. But anyway, let's not forget that Wikipedia is an open-source service and it needs to continue its development as well.