One of my favorite interactive designs over the past few years has been NPR's Book Concierge. It has changed a bit over the years, and it's particularly great this year. It's responsive to screen size, and when you choose filters the book covers whisiclaly rearrange themselves.
You can select from a variety of filters including things like "science" "ladies first" "family matters" and so forth. Hovering over a book cover gives you a blurb about it and clicking on a cover brings forth a longer description of the book.
Most online book browsing experiences leave a lot to be desired (ahem, Amazon) and I still find myself more likely to do serious browsing in a good old fashioned book store. This design puts a bit of fun back into online browsing and it leverages movement and the visuals of the covers to engage book lovers.