The present invention relates generally to methods for activating and expanding cells, and more particularly, to a novel method to activate and/or stimulate cells that maximizes the expansion of such cells to achieve dramatically high densities. In the various embodiments, cells are activated and expanded to very high densities in a short period of time. In certain embodiments, cells are activated and expanded to very high numbers of cells in a short period of time. Compositions of cells activated and expanded by the methods herein are further provided.