The office in Midtown was laid back, dark, and quiet. Macs were perched at every desk and additionally I spotted a couple speed bikes hanging out in the corner.
Based on the atmosphere of the Tumblr head quarter office, one might more accurately guess it to be in Brooklyn rather than Manhattan. However, because of the age of founder David Karp, its atmosphere made sense. (He is only 25.)
Read more about the Tumblr history here.