I believe the common thinking among the scientific community is that about 1 pound per week is a safe rate for weight loss. And of course we must realize that every human being is at least slightly different (some are VERY different) and therefore there will never be one right answer but instead there will be an answer for you.
That having been said, I am well aware of competitive athletes trying to make weight by expectorating and sweating. This is obviously a loss of water weight and would likely be both temporary and dehydrating.
For the person wanting to move toward their optimum weight (which may mean losing or gaining) it's best to look at their eating habits including the way they combine proteins, carbohydrates, and fats in addition to their level of activity. This sort of awareness, followed by appropriate adjustments will bring you to an optimum weight over time.
I agree with some of the above- there's no real quick way in my opinion. But if you're getting ready for an event this weekend or something in a short amount of time, there are ways to appear a bit slimmer...
I'm a big champion of cutting out most of the sodium in my diet for the days leading up to whatever event you're attending. That and all water and no alcohol... (or basically just NO SODA or carbonated beverages that can make you feel bloated)
I'd say your best bet with "week of" workouts would be interval training of any kind... but that's just my opinion...
I know this is not what you want to hear, but there are no shortcuts... Eating properly (i.e.: smaller portions, adding veggetables, eating ballenced meals with lean protein and complex carbs...), excercising and building some muscle (burns fat) are the best ways but that takes time. Of course, water is also very important.