I did an awesome one a couple of years ago - you just cut out alcohol, caffeine, sugar and dairy. I did it for four weeks, but you could do more or less, I suppose. I also did the detox juice thing and had carrot and celery juice every day.

I lost about 5kg and felt amaaazing.

You could go to your library and check out the liver cleansing diet, if you're looking for something fairly easy.