(This first appeared in the grammar pages of the site, but hey... you might not read the grammar pages.) 

Once there were four managers.  Their names were: Somebody, Everybody, Anybody, and Nobody.  They were very busy people, but whenever there was an important job to be done, Everybody was sure that Somebody would do it. Anybody could have done it, but Nobody did it. When Nobody did it, Everybody got angry because it was Everybody's job. Everybody thought that Somebody would do it, but Anybody realized that Nobody would do it. So consequently Everybody blamed Somebody when Nobody did what Anybody could have done in the first place.