The Great Lakes hold 20 percent of the world’s fresh water, and we’ll need every bit of it if the $100,000 shower ever catches on in Chicago. We’ve told you about spa amenities in condo buildings and ultra-luxurious personal showers before, but the SilverTAG Shower shamelessly puts them all to shame. The SilverTAG’s 18 handblown glass showerheads flood the user with 65 gallons of water per minute in a feat of “hydro-gymnastics,” and computer-programmed therapies use alternating pressure and temperature to stimulate ideas, treat cellulite, wake a person up or flush out that handle of Stoli from the night before. The shower was originally designed for a Hollywood producer who said he dreamt up his best ideas in the shower (and thank goodness, otherwise we might never have gotten Snakes on a Plane). In the ultra-luxury market, where the sky (or the depth of Lake Michigan, in this case) is the limit, will spa showers like this one ever become the must-have for well-to-do buyers?