In the last decade, a two-dimensional bosonic system called microcavity exciton-polariton has emerged as a new, promising candidate of Bose Einstein Condensation (BEC) in solids. Many pieces of important evidence of polariton BEC have been established very recently in GaAs and CdTe microcavities at liquid-helium temperature, opening a door to rich many-body physics inaccessible in experiments before. In parallel with experimental progresses, theory and numerical simulations are developed, and our understanding of the system has greatly advanced. In this article, we review the recent experimental and theoretical results obtained at Stanford University.