One of the biggest current methods of "demand response" is shifting HVAC loads from large commercial buildings: pre-heating or pre-cooling by a few degrees, and then lessening the HVAC activity during the peak time. This can be done at the residential level with devices like a Nest thermostat, and be overridable by the customer if they don't want to save the $0.25 or whatever.

Water heating is even easier to implement this way, but requires smarter water heaters.