The Shamrock Shake Challenge | ZUG: For St. Patrick's Day this year, I was trying to drink one gallon of McDonald's Shamrock Shakes. Yes, one gallon. 128 fluid ounces. In one sitting. Why? Well, besides the obvious wiseass retort of "Why not?"(usually good enough for me) there's also the burning urge to refute the stereotype that we Irish are all about alcohol. I'm here to prove once and for all that we can binge drink anything, not just booze.