The game is based around 96 Wacky cards - each with a wacky thing to do, a point value 1-12 and some with either 'Always' or 'Whenever' written on. There are also 4 prop cards and 4 props - funny glasses, a feather boa, an echo microphone and an elephant nose - with detailed instruction on what to do if you have one of these cards.
The 4 youngest players randomly pick a prop card then take that prop. Wacky cards are shuffled and placed facedown within reach of all. On your turn take a Wacky card, place it face up in front of you and read it aloud to all players. You then do the wacky thing - and if it's marked as an Always card you repeat it every turn; if it's marked as a Whenever card it will be whenever someone else does a particular thing.
The object is to be the player who gets the most points for doing wacky things over an agreed number of rounds. Add up the points on each player's cards - highest points wins.