Something Aweful presents The Art of Wikigroaning:
The premise is quite simple. First, find a useful Wikipedia article that normal people might read. For example, the article called Knight. Then, find a somehow similar article that is longer, but at the same time, useless to a very large fraction of the population. In this case, we’ll go with Knight. Open both of the links and compare the lengths of the two articles. Compare not only that, but how well concepts are explored, and the greater professionalism with which the longer article was likely created. Are you looking yet? Get a good, long look. Yeah.
The article lists a lot more examples…
I use Wikipedia all the time, but I have to admit that some entries show that many people have way too much time on their hands… 😉