Rotation with thermally induced buoyancy governs many astrophysical and geophysical processes in the atmosphere, ocean, sun, and Earth's liquid-metal outer core. Rotating Rayleigh-Benard convection (RRBC) is an experimental system that has features of rotation and buoyancy, where a container of height H and temperature difference Delta between its bottom and top is rotated about its vertical axis with angular velocity Omega. The strength of buoyancy is reflected in the Rayleigh number (similar to H-3 Delta) and that of the Coriolis force in the Ekman and Rossby numbers (similar to Omega(-1)). Rotation suppresses the convective onset, introduces instabilities, changes the velocity boundary layers, modifies the shape of thermal structures from plumes to vortical columns, affects the large-scale circulation, and can decrease or enhance global heat transport depending on buoyant and Coriolis forcing. RRBC is an extremely rich system, with features directly comparable to geophysical and astrophysical phenomena. Here we review RRBC studies, suggest a unifying heat transport scaling approach for the transition between rotation-dominated and buoyancy-dominated regimes in RRBC, and discuss non-Oberbeck-Boussinesq and centrifugal effects.