This is one of the things I love about NYC: freedom of expression. The streets are outdoor art galleries. I found this particular exhibition on Crosby Street on my way to work. I don't know who the artist is, but I don't think he/she is concerned about being recognized.
There's an old, abandoned elevator outside the door to my work building that's also covered in artwork. However, there is a local artist who apparently leaves free paintings at this elevator every Friday. A coworker was lucky enough to score a pretty big art piece last week before someone else found it.
I think street art might be the theme for my next photography project.