  We show theoretically that the Coulomb drag rate between two parallel
quasi-two-dimensional electron gases is substantially enhanced by the coupled
acoustic and optic plasmon modes of the system at temperatures $T \gtrsim
0.2T_F$ (where $T_F$ is the Fermi temperature) for experimentally relevant
parameters. The acoustic mode causes a sharp upturn in the scaled drag rate as
a function of temperature at $T \approx 0.2 T_F$. Other experimental signatures
of plasmon-dominated drag are a $d^{-3}$ dependence on the well separation $d$,
and a peak in the drag rate as a function of relative carrier densities at
matched Fermi velocities.
