  We show that the exoplanet HAT-P-7b has an extremely tilted orbit, with a
true angle of at least 86 degrees with respect to its parent star's equatorial
plane, and a strong possibility of retrograde motion. We also report evidence
for an additional planet or companion star. The evidence for the unparalleled
orbit and the third body is based on precise observations of the star's
apparent radial velocity. The anomalous radial velocity due to rotation (the
Rossiter-McLaughlin effect) was found to be a blueshift during the first half
of the transit and a redshift during the second half, an inversion of the usual
pattern, implying that the angle between the sky-projected orbital and stellar
angular momentum vectors is 182.5 +/- 9.4 degreees. The third body is
implicated by excess radial-velocity variation of the host star over 2 yr. Some
possible explanations for the tilted orbit are a close encounter with another
planet, the Kozai effect, and resonant capture by an inward-migrating outer
planet.
