I have to agree that losing 20 pounds in 10 days is probably not possible, and in any case it's really not a good idea. Having said that, however, Fran McCullough's "Living Low Carb" offers some ideas on emergency weight loss:

"First of all, pull out all the stops with the supplements: liver cleansing, L-carnitine, omega-3s. Drink even more water than usual - a gallon a day wouldn't be too much - and exercise even more than usual. Eat enough protien but not too much, and try to keep it to fish, eggs, and protien shakes. Cut back drastically on the dairy products or eliminate them altogether. Keep fruit to an absolute minimum. Drop the alcohol. Be careful about nuts, and emphasize green vegetables and salad. Check to be sure your calories are somewhere between 1,200 and 1,500, depending on your size.

"Don't follow this regimen for more than two weeks at a time; you don't want to send your body into starvation mode, which will slow down your metabolism and leave you with a permanent limited calorie budget (McCullough 65)."

Hope that helps.