What is Ashtanga yoga?

Ashtanga Vinyasa Yoga is the name given to the system of hatha yoga currently taught, in Mysore, South India, by Sri K. Pattabhi Jois, a former student of Krishnamacharya.
In Ashtanga Vinyasa yoga, postures (asanas) are arranged in sequences, called series. There are six such series, although most practionners only study the first one, Yoga Chikitsa, which is generally called the primary series.
The asana practice in this style of yoga is fast flowing and aerobic. It begins with a number of repetitions of Surya Namaskar (sun salutations), and the various asanas are linked between them by a transition sequence called a Vinyasa, in which movement is consciously synchronized with the breath. The ashtanga system also makes  use of a special breathing technique (Ujayi) and of internal energy locks (Bandhas) to produce intense internal heat and a profuse, purifying sweat that detoxifies muscles and organs. Emphasis is also placed on drishtis (gazing points).
The practice of Ashtanga Vinyasa yoga develops strength and stamina as well as flexibility, as well as being very energising.
For more information, see the ashtanga links section of this site