UPPER JAY Peter Walker came up in the Cambridge Mass. and Greenwich Village folk scenes of the 1960's. He recorded two albums for the Vanguard label in the late 1960's. Their style can be best described as American Folk-Raga. He studied with Ravi Shankar and Ali Akbar Khan, and was Dr. Timothy Learys musical director, organizing music for his celebrations. Walker settled upstate in the early 1970's. Over the past few years, Walker has developed an intense interest in flamenco guitar, and regularly visits Spain where he has been accepted into a very exclusive musical society. He will perform an exclusive engagement at the Recovery Lounge on Friday, May 23 at 8 p.m. Tickets are $10. Reservations are suggested.