This is my current favorite Weird Al song, and is particularly apposite given all the furor about Michael Jackson's recent demise. It is, and must be, a link, because embedding is disabled for this video--but totally worth 5 minutes on YouTube.
A warning: if you have not heard Bad, by Michael Jackson, it verges on the uncomfortable, being essentially fat jokes (I am probably over-sensitive on this point--I watched it without having heard the song it's a parody of, and I am profoundly uncomfortable with poking fun *at people* [though I poke fun all the time]. So my first reaction may not be the best gauge). But if you have heard Bad, and especially if you have watched the music video for Bad--O.M.G. hysterical. As a matter of fact, if you watch the original music video immediately after the parody, I can almost guarantee that you'll laugh out loud.
Weird Al is probably the greatest parodic genius ever, and most certainly the greatest parodiest I have ever encountered (is parodiest a word? It is now, at least). Carol Burnett comes close, perhaps--have you ever seen Went with the Wind? Go, watch it now--it's on YouTube. Anyway, he is partly so fabulous because he copies not only meter and line (while completely changing the sense), but also he satirizes the singers, and the videos, nearly as perfectly (some things have to be changed, necessarily, to make the jokes, but he never derails the copy for the sake of the joke).
In short, Weird Al is really funny, and you can spend hours on YouTube, minion of evilness, watching the 25 or so authorized videos (which are not all songs), as well as the scads and zillions of shaky concert home videos and attempts at home to Be Weird Al.