Stumbleupon but for knowledge — this could actually work. You stumble knowledge of particular subjects instead of blog posts and comics. Very interesting. Cool idea, lots of fun I've been generating ideas for 20 minutes now.
* http://xkcd.com/903/ (see tooltip) (and corresponding wiki entry: http://en.wikipedia.org/wiki/Wikipedia:Getting_to_Philosophy)
* http://en.wikipedia.org/wiki/Special:Random
So agree, this sounds like a fun idea!
Basically, "I found an interesting article on Wikipedia".