Guru Purnima is observed on the full moon day (Purnima) in the Hindu month of Ashada (June - July). The day is dedicated to the Guru - one who dispels darkness. Guru is honored and given due respect on Guru Pada Puja day.

The Guru Gita in the Skanda Purana hails guru in this famous verse:

"Guru Brahma Guru Visnú Gurur Devo Maheshwaraha

Guru sakshat Parambrahma tasmai Shri gurave Namaha"

" Guru is Brahma, Vishnu and Shiva,

Veneration to the Guru who has manifested as Parambrahma."

The true Guru is a transmitting medium, a transporting agent and transparent embodiment of the divine grace and compassion, the focal point of the timeless eternity and finite time.

A real Guru not only points the direction to the goal but takes the consciousness of the surrendered disciple into his consciousness and makes the inflow of the Higher into the lower continuously, till the three consciousness of the Eswara, the Guru and the Atman of the disciple become one undifferentiated whole.(Extract from the preface of Prabodha Sudhakara published by Samata Books.)

Ramakrishna Paramahamsa says about true guru like this:

He alone is the true teacher who is illumined by the light of true knowledge.

Bees come of themselves to the full-blown flower when the breeze wafts its fragrance all around. Ants come of themselves to the spot where sweets are placed. No one needs to invite the bee or the ant. So when a man becomes pure and perfect, the sweet influence of his character spreads everywhere, and all who seek the Truth are naturally drawn towards him. He need not go in search of an audience to listen to him.

It is very hard to find a true and real Guru in the modern day but luckily the great Saints of Sanatana Dharma stored their wisdom in the Upanishads, Yoga Vashista and Gita.

A Guru need not always be a person clad in saffron or white, it can be a book, an incident, a small child or any aspect in nature. Any person or incident that removes darkness and fills with light or Brahman realization is a Guru.

Special Puja's and rituals are held on the day. Satsangs and meetings are held to honor Saints.