For thousands of spiritual seekers, particularly in South India, it&rsquos become a no-brainer. Whatever else they may do through the year, they know they&rsquoll be spending Mahashivaratri &mdash the fourteenth day of the lunar month of Magha &mdash at Isha Yoga Center, at the Velliangiri foothills in Tamil Nadu. The Isha Foundation is an organisation founded by Sadhguru Jaggi Vasudev, and the Yoga Center &mdash a green settlement surrounded by mist-kissed hills &mdash is a beautiful place, the seat of the fourteen-foot Dhyanalinga.