crystals are colored directed graphs encoding information about lie algebra representations. kirillov-reshetikhin (kr) crystals correspond to certain finite-dimensional representations of affine lie algebras. i will present a combinatorial model which realizes tensor products of (column shape) kr crystals uniformly across affine types. some computational applications are discussed. a corollary states that the macdonald polynomials (which generalize the irreducible characters of semisimple lie algebras), upon a certain specialization, coincide with the graded characters of tensor products of kr modules. the talk is largely self-contained, and is based on a series of papers with a. lubovsky, s. naito, d. sagaki, a. schilling, and m. shimozono.