I know from the Master Cleanse Forum that people are generally reluctant to give the recipe straight because it is highly recommended that everyone read the entire book (easy to do in one sitting and its free online) before trying to attempt the master cleanse. Also the recipe given in the previous post is not The Master Cleanse recipe from the book by Stanley Burroughs. If you would like to a be a master cleanse purist his (the original) recipe is as follows:
10 oz spring or distilled water
2 tbsp. Grade B (or Grade C if you can find it) maple syrup
2 tbsp. fresh, organic lemon juice
1/10 tsp cayenne pepper
Drink 6-12 servings a day depending on hunger, but be sure to drink at least 6.
The only alteration he recommends is reducing to 1 tbsp of syrup if you are doing The Master Cleanse as a reducing fast (i.e. you want to lose weight.)
There are also other components to the cleanse such as a laxative tea and a salt water flush. There are also instructions in the book on how to come off of the cleanse, which is the most important part.