I know expecting rigorous science from an entertainment program is always asking a bit much, but the Penn & Teller gourmet-water prank always struck me as flawed given the social dynamics at play. Most people in that situation are going to feel some social pressure to acknowledge some sort of qualities in what they are being served, whether from fear of appearing unsophisticated or simply out of a desire to be polite, even if what they're drinking does consciously taste like tap water to them.<p>Personally, while I don't buy any branded, single-serve waters, I do actually buy gallon jugs of house-brand "drinking water" from my local grocery store for the taste. Whatever minerals they add "for taste," I prefer it to tap or even spring water.