Last year, I directed the concept development of a rowing app that has gone on to get quite a reasonably sized organic following. Its success was very much unpredicted, but post-rationalising and having read 'the Hook model' by Nir Eyal, I noticed that we had ended up incorporating quite a few design patterns from the book.
Hopefully we'll get the budget to develop the app further, as there are plenty of more ideas learned from the book that we could incorporate. The slideshow below is a nice summary of the concepts, but I recommend supporting Nir and getting the book on amazon here: