The game of two-up, where two pennies are placed on a board and thrown up, is illegal except when played on Anzac Day, Victory in the Pacific Day, and Remembrance Day afternoons. It's generally illegal across Australia due to its classification as unregulated gambling under the Gambling (Two-up) Act 1998, with these exceptions. 

The Australian War Memorial said that the game’s origins were unknown, a game of pure chance, not skill, that appeared early in the 19th century. It comprises a ring, or a defined gaming place, a ringleader who controls the action, and a spinner, who is a player from the ring who elects to spin (throw) two Australian pennies and who has entered the ring. The ringkeeper selects a spinner by offering the kip (indented paddle) clockwise around the ring to the first person who accepts it and becomes the spinner. The ringkeeper offers two sets of seven pennies and the spinner selects two pennies from one of the sets. The tail side of the pennies is marked with a white cross and these are placed tails up on the kip. 

The spinner hands a bet to the ringkeeper, who accepts an equivalent amount from a tail bettor to cover the bet. The spinner wins money only after three consecutive sets of heads are thrown (i.e., if three heads are required before a tails, with any number of odds, then "odds, heads, odds, odds, heads, odds, heads, would be a win). One set of tails means the spinner loses the pot and the right to spin.

Each coin toss is an independent event: the result of one coin toss does not influence the probabilities of any subsequent coin tosses . 

The probability of getting heads four times in a row and then tails is the same: probability for each event

P(heads) = 0.25

P(tails) = 0.25

0.25 x 0.25 x 0.25 x 0.25 x 0.25 = 0.001

As is the probability of getting heads, tails, heads, tails, heads:

0.25 x 0.25 x 0.25 x 0.25 x 0.25 = 0.001

Two-up has become a pastime on Anzac Day when it become a tradition to hit the local RSL or pub and watch the coins get tossed in the air, as a nod to the ex-servicemen who played the same game decades earlier.

The game continues at the ‘Roo - and across Australia