I was surprised to not find Vipassana Meditation listed here. Beginning in 1998, I have attended many 10-day residential Vipassana Meditation courses as taught by S N Goenka. The courses are very serious undertakings with a full timetable of meditation from 4:30 am to 9:00 pm each day.
Students make a commitment to a number of moral principles to maintain a proper atmosphere for the course - no alcohol, drugs or intoxicants, no lying, no sex during the course, etc.
For the first 3 1/2 days the observation of breath is practiced (anapana) with students just trying to keep their full attention on the breath as it enters and leaves the nostrils. When the attention wanders it is brought back as soon as the student realizes. This develops the powers of concentration as well as awareness of more subtle bioelectric phenomena happening in the body in this area.
For the remaining days students observe sensations throughout the body (vipassana). Every type of sensation is observed with equanimity (an even mind free from craving or aversion). Old mental complexes rise to the surface and pass away. This is a very powerful practice which goes far beyond anything I had ever experienced in my life before.
The important thing about the technique is that it is experiential. It is like suddenly having a new sense, like being able to see when previously one was blind. This is a truly life altering experience. It is also a major commitment. To keep up the practice involves 2 sessions of 1 hour per day meditating and at least one 10-day course each year.
On the last day students practice a meditation of good will towards others (metta).
It is important to say that Vipassana should only be learned from a proper teacher within the tradition. You cannot learn from a book. You can be set badly astray by having a self-appointed teacher.
See
http://www.dhamma.org/ for more info about Vipassana Meditation. I am happy to answer questions.