I made one that I thought had really kept the spirit of the original. I changed the thing 100%, yet the words I used had the same look, feel, nearly the same number of syllables, etc as the original (as if you are parading a song, you cannot add words or many syllables). I thought the end result was quite funny. Unfortunately, people here just won't give a thought to the effort that goes into good parodies. They blindly say parody = suck. That simply isn't true for some. Of course the majority bomb since they violate the spirit of the original post or they have no humor at all.