Common-envelope events capture the imagination and are visually impressive, energetically noteworthy, and dramatically fate-defining episodes in the lives of close binary systems. During a common envelope event, two stars temporarily orbit within a shared envelope, and the episode ends with an exciting outburst, leaving behind either a significantly shrunk binary, or a single merged star. These events are believed to be vital for the formation of a wide range of extremely important astrophysical objects, including X-ray binaries, cataclysmic variables, close double-neutron stars, and the potential progenitors of Type Ia supernovae and gamma-ray bursts.  I will review the basics of the common envelope physics, the recent progress that was made by the inclusion of recombination physics, as well as new perspectives that opened up by observations of a new class of astronomical transients, Luminous Red Novae.