When I hear the term "Slot Machines" my eyes tend to glaze over as I recall the opulent, fashionable themes of the casinos in Las Vegas. It's like stepping into another world with the choice being yours as there are so many now.
First - a bit of history.  Charles Fey of San Francisco, CA is credited with the invention of the slot machine. It was believed that his first envision of the machine was in 1895 but it was not until 1897 he produced his first prototype. It has only 3 reels and they displayed a combination of five symbols - horseshoes, diamonds, spades, hearts and a Liberty Bell and the payout was determined by which symbols were disclosed in a row on the machine. The "Liberty Bell" as it was called was unexpectedly popular and therefor copied by a number of manufacturers. This new form of entertainment was given a number of creative names. It was referred to as "slot machine" in America, a "fruit machine" in Britain, "the slots" in English Canada and "pokies" in English Australia and New Zealand. The "One Armed Bandit" was a popular phrase used as well since since the originals machines operated by pulling a lever on the side of the machine and very often relieved the hapless get-rich-quick player of all of his hard earned money.
By 1908 many cigar stores, saloons, brothls and barber stores had installed them for their customers entertainment.
Fast forward to the 1980's. As with most technology the inner workings of the slot machine became a computer program and when embellished with all of the bells and whistles the modern machine took shape. Those machines that were set up with around 10,000 possible winning and losing combinations changed and increased to over 16 million possibilities.
The video slot machine changed the industry again when it dispensed with moving parts (reels) in favor of graphics. Essentially - the video slot machine was a computer game. Now the sky was the limit on how the game was presented, the amount of interaction between player and machine and bonus spin off games were incorporated into the experience.
Those who built the machines and the entrepreneur s who installed slot machines in their establishments quickly discovered the value of the "near miss" and the machines were programmed to draw attention to the near misses as an indication the big "win" would be forthcoming. Researcher Luke Clark explains the attraction of the "near miss" in Discovery Magazine. 
Researcher Luke Clark in the above mentioned article states: "Gambling has essentially hijacked the natural reward system .... and he adds that it's not only gambling addicts who have to worry about being driven by their own brains." Importantly, our volunteers in this study were not regular or problem gamblers, and so these findings suggest that the brain may naturally respond to near misses in this way. "
As a safe alternative [I say safe alternative with the stipulation that one plays only on sites like Pogo.com and plays without betting] there are computer gaming sites such as Pogo.com that have the most imaginative themes for their slot machine games. There are hours of entertainment available without destroying lives or lifestyle.
Here's the thing ... if you enjoy slot machines just for the entertainment value, try the fun and games online at places like Pogo.com. It is always a good laugh and one can enjoy a rainy afternoon or if you are a Canadian and live in the Great White North, pass the time when it's -30 with a nasty wind blowing. I say this because that's how I got started. It's great fun.