I attended Spotify's "diversify" hackathon and loved every bit of it.
It was pretty different from other hackathons I've been to: everyone was relaxed, people didn't pull all-nighters (most people stopped around 11PM and started back at 9AM) and the crowd was indeed diverse: a strict 50/50 ratio between male and female participants, Swedish AND international students, and everything from designers, front-end/back-end developers to marketing specialists!
Overall, the experience was pleasant and I hope other "mainstream" hackathons will also try to encourage a more diverse participation (because it really impacts the final products and the way it's built).
I encourage you to read Michelle's post (in English and Swedish) about the hackathon. Michelle was part of my team (Beautiful World) with the other members being Johan and Meike. We've built "Beautiful world", a web app that combines browsing pictures with listening to music (and implements a simple recommendation system using data from Spotify's and EchoNest's API). The code is available on github.