The Exceedingly Good Song Night, led by Ken Schatz, is indeed an exceedingly good session for singers. The Folk Music Society of New York (aka New York Pinewoods Folk Music Club) is another source for singing, holding several informal participatory singing gatherings every month, including the Chantey Session at the Seaman's Church Institute that Charlie mentioned. See the Folk Music Society's web site at www.folkmusicny.org.
We welcome all who like to sing or play folk/roots music.