Interesting topic. We need energy as a society, so any conversation that starts out with 'let's give it a try' about not using energy is mute.
I think it's possible to greatly reduce current energy consumption significantly if we really try.
Phase out all incandescent lighting over the next 10 years. Produce only CFL's. The reduction in energy by simply doing this one thing is enormous.
Build more nuclear power plants. No one wants them, including me, but how else to you stop buring fossil fuel AND make sufficient energy in the short run, ie 50-75 years.
Crank up the tax credits for solar energy use...residential and commercial applications alike.
I think for the hundreds of billions we spent in Iraq, we could have developed a battery that could hold double or more the amount of energy the current hybrid battery technology allows.
Also, mandate maximum insulating qualities in new construction, no minimum.
Make car pooling and public transportation more attractive. Don't ask me how, just an idea.
Make every car E85 capable and start using other sources than corn to do it. You could get millions of acres planted with switchgrass in Mexico and produce ethanol much more cheaply than we do here. That would be good for Mexico and allow us to stop importing so much oil into the US.