This one in particular uses the jQuery onepage-scroll plugin [0] for the scrolling effects, prism.js [1] for code syntax highlighting and some plain HTML and CSS. Here's the complete code: https://github.com/emisfera/Splitchar.js/tree/gh-pages.
In reference to some other comments on this thread, this isn't built using Jekyll. GitHub pages supports pure static sites and Jekyll-powered sites if you put either on the gh-pages branch of the repository.
You're right, thanks. I'm finally home and managed to look at the source, it doesn't use Bootstrap. The author built it all from scratch. Kudos to him.
Hiding your content below the scroll and having a single, tiny, ambiguous, low-contrast visual indicator that more information is below seems to be "the in thing" in web design in 2014.