Harinaam, brief for Harinaam-Sankirtan (the congregational chanting of the holy names of the Lord) may be most acquainted from looking the devotees out in the streets, chanting and dancing the maha-mantra Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare accompanied by karatalas (hand cymbals) and mridangas (two headed drums).
This activity creates and spreads transcendental vibration of sound by chanting the names of lord loud out. It purifies the environment and makes the lightens-up the mood of over lookers.
Lord Chaitanya Mahaprabhu appeared over 500 years ago, was the leading advocate of the path of Bhakti and He initiated the chanting of the holy names of Lord Krishna in the form of the Hare Krishna maha-mantra. Sri Chaitanya was Lord Krishna Himself who founded a spiritual revolution by spreading the Sankirtan movement throughout the India.