For an excellent article on Shivaratri by Dadaji which explores the historical and esoteric significance of Mahashivaratri, go to an earlier posting on Arunachala Grace at Mahashivaratri -- Story of an Eternal Festival.
Which begins:
"Once celebrated on a vast scale throughout India, it now only sees peak performance at two places, separated by a considerable distance as well as a border. The best celebration to be witnessed is at the Pashupatinath (Lord of Animal Life) Temple at Kathmandu, Nepal. The other is celebrated on the Teleti, the sacred area at the base of Mount Girnar in Saurashtra."
Mount Girnar