Encountered this a while back on rathergood.com; no idea whether it's by them or by someone else:
And the princess lived happily ever after until she got executed in a basement by the glorious leaders of the revolution THE END
Plot plus a commentary on the monarchist tendencies of the fantasy genre, all in 21 words! Or 23 if you count THE END.
(Wrote this entry back in January, somehow never posted it.)