I'm doing this for a week:
http://www.cabbage-soup-diet.com/eating-plan.html
Dan and I love making soup anyway (and he's said he's going to join me in the diet for moral support

), and you can mess about with the
recipe with spices and herbs to make it more interesting. It's just loads of fruit and veg for a week, with some potatoes and beef mixed in for good measure. It sounds pretty good, and apparently it works to kick start your diet.
I'll probably do this for the week before my ball and see how it goes, and then switch to simply 'healthier eating' after that. And definitely more exercise.