  The relaxations of conductivity after a temporary change of carrier density
n_s during the waiting time t_w have been studied in a strongly disordered
two-dimensional electron system in Si. At low enough n_s < n_g (n_g - the glass
transition density), the nonexponential relaxations exhibit aging and memory
effects at low temperatures T. The aging properties change abruptly at the
critical density for the metal-insulator transition n_c < n_g. The observed
complex dynamics of the electronic transport is strikingly similar to that of
other systems that are far from equilibrium.
