After midnight of every day. Technically it's the next day, but doesn't the next day really start when you wake up in the morning? Therefore; anything happening between midnight, and before you go to bed doesn't really fall into a proper day's definition, and technically never happened. Particularly useful while partying all night.
We were so shit-faced we nailed a picnic table to the neighbors house at 4am last night. Technically, that never even happened cause it was on noday.
To speak tirelessly about one's own humdrum life regardless of the topic at hand.
He totally noday'd the conversation!