Mahāśivarātri — the great night of Śiva
Phālguna Kṛṣṇa Caturdaśī (Māgha in amānta) · February–March
Every month has a Śivarātri on the fourteenth night of the dark half, but the one before the new moon of Phālguna is Mahāśivarātri, the great night of Śiva. It is a night of stillness rather than celebration: fasting, staying awake, and worshipping Śiva as the liṅga, the formless made visible. Tradition calls it the night Śiva and Pārvatī were wed, the night Śiva appeared as an endless pillar of light, and the night of his cosmic dance.
At home, keep a fast as you are able — many take only fruit, milk and water, some keep it nirjala — and break it the next morning. Worship Śiva in the evening and, if you can, through the four praharas (watches) of the night. Bathe a small liṅga with water and then milk, curd, honey, ghee and sugarcane juice, rinsing with water between; offer bilva (bel) leaves with three leaflets, white flowers, dhatūrā, sandalwood paste and vibhūti; light a lamp and incense. Chant “Om Namaḥ Śivāya” — the pañcākṣara mantra — or the Mahāmṛtyuñjaya mantra, read the Śiva Purāṇa or listen to Śiva bhajans. Staying awake in prayer (jāgaraṇa) is itself the vrata.
The twelve jyotirliṅgas — Kāśī Viśvanātha, Somanātha, Mahākāleśvara at Ujjain and the rest — draw vast crowds, as does Paśupatinātha in Kathmandu. Kashmiri Pandits celebrate it as Herath with special pūjās and walnuts. In the South, temples hold all-night abhiṣekas, and in Mauritius pilgrims walk to the lake of Ganga Talao.
Tradition tells of a hunter who, lost in the forest at nightfall, climbed a bilva tree to escape wild animals. Hungry and afraid to sleep, he plucked leaves through the night and let them fall — onto a Śiva-liṅga hidden beneath the tree — while drops from his water-gourd trickled down on it too. Without knowing it, he had fasted, stayed awake and worshipped Śiva on Śivarātri; when dawn came, his heart was changed, and he was granted Śiva's grace.
Another story says that Brahmā and Viṣṇu once argued over who was greater, when a blazing column of light appeared between them. Brahmā flew upward as a swan and Viṣṇu dug downward as a boar, but neither found its end. Śiva then emerged from the pillar — the first liṅga — and both bowed to him.
Śiva · Pārvatī · Night vigil, abhiṣeka, bilva leaves · Twelve jyotirliṅgas, Paśupatinātha · Śiva Purāṇa (Koṭirudra Saṃhitā)