Complete a level and if the last 2 digits of the timer match excluding 00, Fireworks will appear and Toad will also give you an Item. Below is the list of the items unlocked by their matching timer digits.

Item	Location
Fire Flower	Last 2 digits equaling 33 or 34.
Ice Flower	Last 2 digits equaling 55.
Star	Last 2 digits equaling 88 or 99.
Super Accorn	Last 2 digits equaling 77.
Super Mushroom	Last 2 digits equaling 11, 22, or 66.