Unsupervised Feature Learning and Deep Learning: A Detailed Tutorial (2013)

This is a great resource, and I'm sure it may have improved in the three years since I last looked at it. There was also a HN submission from back then that has some interesting discussion:

(167 points, 1018 days ago, 16 comments)

https://news.ycombinator.com/item?id=5769646

I believe this is the updated version.

http://deeplearning.stanford.edu/tutorial/