Intrinsic motivation is the type of motivation that causes an individual to do something for the sheer pleasure of the act. There are no rewards for a person to feel motivated to do a certain act if they possess intrinsic motivation. Another term for intrinsic motivation could be internal motivation, but some types of internal motivation are caused by external stimuli so this is not always an accurate alternative label.
Examples of intrinsic motivation can be seen in small children who love a certain activities such as climbing, or coloring, or building with blocks. Many times children performing these tasks do not need someone to tell them good job, which would be an external reward, or they do not need someone to give them a piece of candy to do the task. They climb or color or build because they simply get pleasure out of the act. Sometimes it can even be detrimental to a child's intrinsic motivation if an external reward is given. Then a child may become dependent on a reward of kind words or even something material where they were originally participating in the act because they found it fun.
Children often lose some of their intrinsic motivation as they become increasingly aware of their environmental stimuli. They begin to be concerned what an adult thinks of what they are doing and thus begin to perform tasks either to avoid discipline or to receive affirmation. This moves a child's motivational base from intrinsic to extrinsic.
Motivation that is driven by external stimuli is considered extrinsic motivation. Extrinsic motivation is different from intrinsic motivation in that extrinsic motivation is caused by some outside influence on the individual.
Mature individuals have to balance their natural intrinsic motivation with their knowledge of the society within which they live. It is not acceptable to act on all of our intrinsic motivation all the time. It is important though to recognize what you enjoy to do for the sheer pleasure of doing it and try to include those activities in your life if possible because out of those things will flow a natural satisfaction and fulfillment.
So when thinking of motivation on a personal level it would be worthwhile to look at things you could spend lots of time on with no outside reward. Some people have intrinsic motivation to exercise where others might have intrinsic motivation to play and instrument or read a book. Whatever it is that give you pleasure just through your participation in an area where you have some level of intrinsic motivation.