I know that I, and many others, have had good luck breaking plateaus by changing the ratio of fat, carbs, and protein, and also by changing up the activities. The body acclimates to what you do, so the theory is that changing it gives the metabolism a wake up call. It doesn't mean that you can sleep all day and eat a tub of ice cream, but changes to the routine do help!
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days