Dev Diwali

Also known as Tripurari Purnima, this occurs on Kartik sud 15 - Purnima. Eradicating inner base instincts signifies Diwali; meeting the Lord is Dev Diwali.

Origin

After leaving king Bali, the Lord rejoined the devas on this day. The devas celebrated His arrival in jubilation and thus Dev Diwali came into being.
Tripurari Purnima. The 7th Skandh of the Shrimad Bhagwat cites the story. With the help of Tarak and Vidyunmaali, a demon named Muy daanav constructed three aerial 'purs' - cities; of gold, silver and iron, which he gave to the demons. With these, the demons flew wherever they wished, destroying the places where they landed. The devas then approached Lord Shiv for succor. Another reference cites that Naradji instigated the 3 demons to destroy Kailas - Lord Shiv's abode. An angered Shiv then destroyed the three purs. Henceforth he became known as Tripurari. The devas rejoiced on this day, hence Dev Diwali.

Sentiments

The sentiments are the same as Devprabodhini Ekadashi. Though the devas celebrated the Lord's return, we mortals celebrate Dev Diwali by eradicating our inner demons - the base instincts of ego, anger, greed, lust, etc. and the resulting manifestation of divinity within.

Other important events in the Hindu Dharma on this day include:

Nimbark Jayanti. In the 12th century, Nimbark Acharya, the proponent of Dwaitadvait philosophy and Sanak Sampraday was born on this day. He was the first to consecrate Radha's murti with Shri Krishna in mandirs, enjoining the eternal principle of dual worship of Bhakta and Bhagvan i.e. to become an ideal devotee like Radha in order to worship Krishna.

Shrimad Rajchandra Jayanti. About 150 years ago, Shrimad Rajchandra was born on this day in Vavania, a village in Saurashtra. Though a Jain, he declared the absolute need of a manifest Satpurush for ultimate salvation.

Tulsi Vivaha. The marriage of Tulsi, Rukmani in a former birth, with the Lord is celebrated on this day.