How many of you have ever loved a product so much that you'd be willing to stake your reputation on it? Or better yet make a laughingstock out of yourself for it? Well these six celebrities were willing to risk it all, if nothing else, for the cash! Take a look at the products they've used to improve themselves. Be sure to let us know if there's an embarrassing celebrity advertising campaign that we've overlooked!

Jamie Lee Curtis

Product: Activia

Desired Effect: "helps regulate your digestive system by helping reduce long intestinal transit time"

Serena Williams

Product: Tampax

Desired Effect: "tough leak protection"

Jessica Simpson

Product: Proactiv

Desired Effect: "a complete approach to treating acne"

Joe Montana

Product: Shape-ups by Skechers

Desired Effect: "Firms buttock muscles, tones and firms thigh muscles, tightens abdominal muscles and firms calf muscles"

Jason Alexander

Service: Jenny Craig

Desired Effect: "help to achieve your weight loss goals"

Jimmy Johnson

Product: ExtenZe

Desired Effect: "providing a a larger penis and enjoying a more fulfilling sex life"