  We report the discovery of one unique cataclysmic variable drawn from the
Hamburg Quasar Survey, HS2331+3905. Follow-up observations obtained over three
years unveiled a very unusual picture. The large amplitude 3.5 h radial
velocity variations obtained from our optical spectroscopy is not the orbital
period of the system, as one would normally expect. Instead, extensive CCD
photometry strongly suggests that HS2331+3905 is a short orbital period
cataclysmic variable with Porb = 81.09 min, containing a cold white dwarf which
appears to exhibit ZZ Ceti pulsations.
