Some time back, we told you that more and more Americans are wearing bracelets. Not jewelry, but little rubber or cloth bands in various colors. Each of them signifies a message: Pink to support breast-cancer research. Orange to raise HIV/AIDS awareness. Burgundy to keep old and sick hospice patients in our thoughts. And so on.

Now, purple is all the rage, though the call to action from these wristbands is a lot less somber.

Purple rubber bracelets are being snapped up by people who want to stop whining. That's right, whining: carping, complaining, criticizing, bellyaching or, as they say in Yiddish, kvetching.

According to the man who came up with idea ? a Kansas City, Mo., minister named Will Bowen ? scientists have determined that it takes 21 days to form a new habit. So to improve your outlook on life, to become more loving and positive and less critical, we need only slip the purple bracelet on either wrist. Then, when we hear ourselves fussing, we simply move the band to the other wrist and start all over again until we've gone three whole weeks without uttering a single complaint.

Apparently America is a more cheerful place, since more than 5 million of these think-positive wristbands have already been sold. They've earned all kinds of unpaid testimonials on the Web from people who say the purple bands have helped them see the good side of others. One girl even said she has cut way down on whining about her big sister. Imagine that!

We do wonder, though: If we catch purple wristband-wearers grumping or grousing, is it OK for us to suggest it's time to switch wrists?

"Complaint-Free World" bracelets are available at no cost, along with "suggested ways of becoming complaint free," from Christ Church Unity in Kansas City, via its Web site.