Slot games are, of course, known by their more common name of the "pokie" although in other parts of the world they are called everything from "slots" and "amusements with prizes" (AWP) to the more formal "gaming machines". The forerunner of the modern slot game (the "one armed bandit") was invented by Charles Fey in San Francisco in 1887 and pokies have developed over the years as technology has allowed them to become more imaginative and interactive. The first electronic slot game arrived in 1963 and 1996 saw the introduction of the first electronic gaming machine with a second "bonus" round.

The aim of any slot game is to achieve a winning combination across the various reels of the game. Traditional slot games had three reels and one "winline" and a payout occurred if a player managed to spin typically two or three of the same object on the win line. These were often images of different fruits – cherries, lemons and similar – which led to them still being known as "fruit machines" in some parts of the world. Nowadays the variety of slots available means that the images a punter has to match can be as diverse as penguins, Egyptian artefacts or pirate treasure.

Slot games are generally a casino’s biggest earner contributing up to seventy percent of their income. With the advent of online gaming it is now possible for punters to play a huge variety of slot games online and there are many, many hundreds of internet based casinos offering slots in addition to their traditional table games.

The main type of slot game available is the "multiline" game. These generally have video screens and most have some sort of "second screen" feature including bonus rounds and additional ways to win. These slots tend to have up to five or six reels and have a multitude of different win lines. Typically, a multiline game can offer up to a hundred different win lines and over three thousand different ways to generate a payout. The game itself identifies wins for the player by highlighting the appropriate winning combination.

Slot games such as these offer the punter many different ways to play. The player can choose how many of the several dozen win lines they wish to play in every spin, and what stake to place on each line. An individual play can therefore range from a couple of cents for playing one or two lines, right up to several dollars for playing dozens of lines for a higher stake. The wins are of course generally proportional to the individual stake.

Whilst they may appear complicated at first, most slot games in the modern age are surprisingly simple to play. The game itself identifies winning combinations and it only takes a small amount of play on a particular game to work out the various intricacies and unique features of that game.

As well as individual wins on a particular slot, many pokies offer a player the chance to win a "progressive jackpot". These jackpots increase with every single play and they are ordinarily linked to a number of machines all contributing to the same jackpot pool. The progressive jackpots can run into thousands, or sometimes millions of dollars and those instances where a lot of publicity is generated from a big slot game win tend to be through a progressive jackpot.

Each individual slot game both in a casino or online has its own "return to player" percentage. This is the amount that the machine is programmed to pay to an individual player and the minimum percentage is generally established by the regulations of law in a particular jurisdiction. For example, the minimum return to player is 85% in Queensland and 87% in Victoria. The minimum payout in Las Vegas is just 75%.

These "return to player" percentages are one of the reasons that slot games are so profitable to a casino. The "house edge" (the casino’s profit as a percentage of the original bet) for slot games is higher than most other casino games including roulette and black jack. On a slot game with a "return to player" percentage of 85%, it follows that the casino is making an average of fifteen cents for every dollar staked on the machine. When you consider that Australia had over a hundred and eighty thousand poker machines in 1999,that is a lot of income for casinos and pubs across the country.

The proliferation of slot games has not been without controversy. The legalisation of these games has been hotly debated since the 1950s and some areas still prohibit the general use of pokies. Western Australia only permits the use of gaming machines in the Burswood Casino and South Australia actually elected a "No Pokies" candidate to their legislature in 1997.

The rules governing slot games and the payouts differ markedly worldwide. Pubs in the United Kingdom, for example, restrict the maximum prize on a gaming machine to around thirty five pounds (around seventy dollars). New Jersey, USA restricts slot games to casinos in Atlantic City alone and several other American states including Indiana and Iowa only permit the machines aboard anchored barges or licensed riverboats.

Slot games are one of the most popular forms of betting and a casino’s staple income. New South Wales alone has an estimated one fifth of all the pokie games worldwide and has more slot machines per capita than the United States of America. If the proliferation of poker machines in pubs, bars and casinos is coupled with the number of online casinos now also offering slot games, there are literally hundreds of thousands of slots to choose from, and potentially millions of dollars to be won.