I love Rifftrax shorts, but this one is especially hilarious: "We Discover the Dictionary."
As Mike, Kevin and Bill point out: "As far as discoveries go, “Discovering the Dictionary” probably ranks down there with Columbus “discovering” America in terms of least impressive feats. First of all, the dictionary, much like America, was already there the whole time. It was just sitting on teacher’s desk, gathering dust. Second, much like America, people were already using the dictionary before these three idiots found it. In fact, it’s hard to argue that anybody could “discover” the dictionary when it’s in fact a book created by other people."