um Learner....all they did was use the JScript 'escape' function in an advanced way...nothing special. You can use document.write(unescape(""));
to defeat it. I believe the RRFN site once had a link to a script like this. Peep: http://www.yuki-onna.co.uk/html/encode.html

EDIT: woops, I missed the second part of the code. I just noticed the hex at the beginning. You're right, it is kind of interesting.