I think adding referenda to the ballot is a great idea.  The best referenda would be ones that both address important policy initiatives and, importantly, implicitly create a negative frame for Bush's policies.  For example, a referendum on renewable energy would creat an opeing for discussion of Bush being in the pocket of Big Oil, which is gouging consumers at the pump, and would highlight his lack of energy policy.  So something like tax incentives for conservation or alternative energy might be good.