I had given Octopress a try a year or two ago. But went back to Wordpress later. Fast forward to now and I'm obsessed with Octopress!
Anyway, the Classic theme is quite boring. So the first place you'd go to is the 3rd party plugins wiki page. There are a couple of great themes available. There’re a bunch of themes based on Bootstrap. I thought of creating my own theme to create a unique experience for my blog. So I started out with Octo-Found. It's based on Zurb Foundation. I've also added Font Awesome.
It's not yet complete, but has got quite some stuff up and running already. I'm yet to implement an off canvas layout for the sidebar. Thus, the responsive design breaks for tables and below. Well, that's it for now. I'll post again once I complete the theme!