In the East Village, there are scheduled shows in Tompkins Square Park and on Astor Place... not to mention several community gardens. This map provides more details.
A special shout-out to Albert's Garden, one of the oldest community gardens in Manhattan (established 1971).
From 6-8 this evening, you can find Just (Jazz) Friends, an ensemble playing vocal and instrumental jazz standards focused on the American Songbook, Brazilian jazz, and occasional forays into pop/R&B classics from the 1960s and 1970s. Poet Davidson Garrett will also make an appearance. Albert's Garden is at 16 E. Second St. between Second Avenue and the Bowery.