Sadhu Baba is often called a Rishi. Here is a nice definition given of Rishi by Devala Rishi in Brihad Bhagavatamrita (2.1.109 tika ) -
ūrdhva-retās tapasy ugro
niyatāśī ca saṁyamī
satya-sandho bhaved ṛṣiḥ
“A ṛṣi is one whose semen flows upward, who is fierce in observing austere vows, who eats moderately, controls his senses, is able to curse and bless, and adheres firmly to the truth.”
From 5th till 7th October 2009 the 23rd anniversary of the sacred departure from this world of Sitanath Kula-Kaustubha Om Viṣṇupad Sri Sri Nikunja Gopal Goswami (Sadhu Baba) is commemmorated at Sadhu Baba's Ashram with Kirtan and Mahotsav.
Sadhu Baba's Ashram is located next to the Bhajan Ashram at Prachin Mayapura, Navadwip Dhama.
We will feel very blessed with the presence and attendance of the holy Vaiṣṇavas.
Here is a copy of the schedule of this year's festival -