Most gyms nowadays run spinning classes ranging from 30mins (beginners) to 90mins (advanced) in duration....most common and most popular being a 45mins class.
It usually takes place in a spinning studio with an instructor to music
Spinning was created by cyclist Jonny G (Goldberg) as a quick and convenient way to train....
Spinning is a great aerobic exercise burning over 400 calories in 45 mins....it takes place on a specially designed stationary spinning bike, which can be adjusted to suit you. (the seat height, handle bars and resistance dial to adjust the intensity of your workout)
During the class you vary your pace... sometimes pedaling as fast as you can, other times cranking up the tension and pedaling slowly from a standing position. This helps you to focus inwardly and work on your mind as well as your body.
Spinning is fatburning and great for toning the legs and glutes and only 45 mins!!! No coordination required!!!
If you are new to spinning...make sure you tell the Instructor so that your cycle is adjusted properly to suit you...you will enjoy the class much more believe me ,-)
Always take water into a spinning class...its a must!
A handtowel
Dont forget to use your deodrant
AND ENJOY 
If you already do spinning....where is your favourite spinning class?