  The CASTOR Calorimeter at the CMS experiment is an electromagnetic/hadronic
calorimeter which covers the very forward region of the detector (-6.6 < eta <
-5.2). CASTOR is a Cherenkov sampling calorimeter, consisting of quartz and
tungsten plates, with an overall depth of 10 interaction lengths, able to
detect penetrating cascade particles. It is segmented in 16 transversal and 14
longitudinal sections. Surrounding the beam pipe, its design is determined by
space constraints and restricted to materials which tolerate a high radiation
level. In this presentation we report on the operational experience and
measurements with the CASTOR calorimeter during the 2010 data taking at the
LHC, with proton-proton and heavy ion collisions. An overview of the broad
physics program which can be accessed with CASTOR, as well as the status of
published and ongoing physics analyses and detector studies are presented.
