Too bad you are closing down. But keeping an "offline" copy is pretty easy.
If you install a local server with something like wamp or uniserver, you can just "move" your forum to your local server. If you keep the SQL dump, and all the files that were online, you can resurrect it anywhere, being on either a local machine, or something on the internet.
But if there is so much good information, I will repeat jgeoff's question: why??
As for poof, gone. Not gonna happen at our board
