Grad night is usually the last weekend in April/first weekend in May. Tons of high school grads meet up at PI in the afternoon and go to the MK for an "all-nighter". Other than the MK perhaps closing a little earlier, grad night will have absolutely NO effect on anyone. AND, if you don't know about it, chances are you won't 'know' about it. We've been there during grad nights for the past 4 years.