I don't believe that term limits for Congress critters will ever come about, unless the Tea Party becomes an actual political party and takes over Congress. But maybe an approach that is almost as appealing would work, namely setting up a mandatory retirement age for all members of Congress (the President is already term limited, so no need for one there). Let's face it, most of these people become creatures of Washington after a certain amount of time in D.C., it doesn't matter which party we're talking about. But forcing members of Congress to face the same retirement age as everyone else would be a tough initiative for Congress to be against, particularly now when the political class is largely reviled. In a nation of 300 million people, it is tough to make the case that politicians can't be replaced.
I like the idea of “weighted terms” In that in order to win each subsequent term you have to get 5% more votes than the last time. So the first win is majority, the second if 55%, third 60% and so on until you hit a cap of 80%.
If they fail to hit the cap on the re-election they are “primaried out” for the run up election and the election is held again two week after the first one.