Fast and effective weight loss pill or crash diet?

I normally don't believe in taking diet pills or doing crash diets or anything like that, but i have an event in a week and I recently went off the atkins after having little sucess with it, and I've gained a few pounds back since I went off it. So does anyone know of a very quick and effective crash diet or diet pill? I know it's unhealthy and I know I'll just gain it all back but I'm becoming desperate.