go figure

from The Collaborative International Dictionary of English v.0.48

Figure \Fig"ure\, v. i.
   1. To make a figure; to be distinguished or conspicious; as,
      the envoy figured at court.
      [1913 Webster]

            Sociable, hospitable, eloquent, admired, figuring
            away brilliantly.                     --M. Arnold.
      [1913 Webster]

   2. To calculate; to contrive; to scheme; as, he is figuring
      to secure the nomination. [Colloq.]
      [1913 Webster]

   {go figure} a phrase used by itself as an interjection to
      mean "How can one explain that?", or to express puzzlement
      over some seeming contradiction. [Colloq.]
      [PJC]