Water cut.

Day 1: 2 gallons of water
Day 2: 2 gallons of water
Day 3: 1 gallon of water
Day 4: 1 gallon of water
Day 5: 1/2 gallon of water
Day 6: 1/2 gallon of water
Day 7: weigh in

Only eat protein and less than 50 grams of carbs a day.  45 min cardio a day.

This is not healthy or sustainable, but it works.. I lost 13 lbs.  I know someone who lost about 20 lbs.

Not sure of the science behind it, but essentially it tricks your body into expelling a bunch of water.  You will piss like crazy. 

It's pretty miserable.