When do you know you've had enough to drink?Maybe it's when the urinal cake in the men's room of your favorite watering hole starts commenting on your marksmanship.That's the premise behind an experimental sober driving initiative taking place in Colorado, following a debut in Michigan last year.During the Labor Day weekend, the men's rooms in 15 Colorado bars were equipped with motion-activated "interactive urinal communicators," or IUCs, all of them bearing the logo of the Colorado Department of Transportation's "Heat Is On" anti-drunk-driving campaign.Once contact is made with the IUC, a jaunty male voice similar that of a DJ on a morning drive radio show chimes in with some play-by-play commentary."Keep a constant stream on this urinal cake and let's see how drunk you are," the cheery IUC voice says, upon "activation."While those remarks are bound to cause some startled bar patrons to send misdirected fire to the bathroom floor, the IUC dude proceeds to deliver a critique to those still making contact with the talking cake."Winner!" the cake shouts to the apparently unimpaired marksmen taking part in the experiment. "Make sure you keep winning and get home safe!"For those whose aim is less than true, comments range from a sarcastic "charming" to "ham-boned," "tipsy" and "uh, where are your pants?"Michigan's IUC used a recorded woman's voice, increasing the startle factor."Hey, listen up! That's right, I'm talking to you!" the disembodied voice told barroom toilet users. "Had a few drinks -- maybe a few too many? Then do yourself and everyone else a favor: Call a sober friend or a cab. And don't forget -- wash your hands!"It's too early to tell what kind of effect the talking urinal cakes have had on reducing drunk driving rates, but they've already made a splash, so to speak, in the advertising world.The aptly named Wizmark advertising firm is taking advantage of the 10 to 20 seconds of undivided attention urinal users provide while going about their business by exposing them to commercial messages that employ "the elements of surprise and humor," according to the company's website.Of course, those taking in such messages are free to record their "no sale" sentiments in an immediate and satisfying manner.Meanwhile, an issue of more pressing urgency is raised by this IUC business.Using the word "cake" in conjunction with the word "urinal" is just wrong.