There is a wide variety of slot machines, and each online casino offers many variations both for free or for real money. Anyway there are only two categories: 3 reel and 5 reel slots. Find out what are the main differences.
Microgaming is hosting some interesting slots tournament. They run periodically and you can participate to different kind of competition. There are also a few free rolls and big contests where you can win some thousand of dollars that will be credited directly in your casino account.