Buddhist meditation is often practiced as part of the so-called "noble eight-fold path", which is a guide for followers of the Buddha. Those who choose to embark on this path are trying to decrease the experience of suffering, and achieve a state a peace. Different branches of Buddhism vary in terms of how central they consider meditation, but it is always a component of the way toward nirvana.
There are a variety of methods which can be employed in Buddhist meditation. Some practitioners attempt to clear the mind of all thought and find a direct route to a state of mental calmness. This straightforward plan may seem simple, but it is often more difficult than it sounds. For this reason many forms of meditation have been adopted, each of which provides a road in, toward that goal of enlightenment.
For instance, a person may try focusing awareness on their own breath. Since anyone meditating has to breathe, it is an always available method. The regular breaths provide a natural rhythm for the mind to concentrate on, and as one becomes more relaxed, breaths become longer and deeper. Also, breathing is necessary, but can also be controlled, so it serves as an activity as well as an object of concentration.
Another method is undertaking a more directly active state by doing something repetitive, such as cleaning a floor, or practicing Tai Chi. Zen monks are well known for keeping their monasteries pristine through constant meditative cleanings. This creates the proper environment for clear thinking as well as providing a meditative act, in the repetitive movement of sweeping, washing, or painting.
A more intellectual form of Buddhist meditation is that of focusing on a "koan" or unanswerable riddle, such as the famous question, "what is the sound of one hand clapping?" The practice is not meant to lead the student to a conclusion, but rather to give the mind a focus during meditation. The experience of reaching enlightenment through such a process does not mean that riddle is no longer useful for meditation, or has been answered. Enlightenment is a state of mindfulness and peace, rather than facts and answers. Buddhist meditation is a way of life, rather than a means to an end.