in my talk i will try to explain the result of my joint paper arxiv:math/0605141 with d. tamarkin and b. tsygan in as popular way as possible. first, i will convince you that the notion of ``homotopy gerstenhaber algebra'' is not so crazy. second, i will recall algebraic structures on hochschild cochains and formulate the main theorem. finally, i will explain the idea of the proof referring to the well known bar/cobar constructions for associative algebras. well, if the bar/cobar constructions are not well known then they will be well known after my talk.