I'd put them in the category of amnemonics in that they are harder to remember than the original, along with the one for the order of the planets:
My Very Earnest Mother Just Served Us Nine Pickles
and variations thereof. See
http://photon.unl.edu/jeff/humor/lists/astronomy-humor.html
or
http://www.tased.edu.au/schools/sheffidh/36/haberle.html