Music lessons. I think they come in 2 or 4 credits, and they're guaranteed easy As. There's group or private lessons, but aside from Piano, I think you have to supply your own instruments. Music and Performing Arts Professions FAQs - Music Department - NYU Steinhardt
Intro to Digital Photography in Steinhardt. I'm in it now, and Steinhardt has DSLRs available for loan, but our teacher let us use point-and-shoots for our assignments. I had an A on my midterm grade.
Supposedly, I've heard that the Irish language classes at the intro level are easy.
Any Intro art class such as Intro to Sculpture or Intro to Drawing/Painting, but only if you're willing to do a bunch of work outside the classroom.
What about one of the Tisch Open Arts? There's always some sort of filler class in there.
I know these are all "artsy" kind of classes, so if you're not really into that, I could suggest other ones.