Elementary OS always caught or users attention because of it's design principles, which lead to a very aesthetic appearance (including the gtk elementary theme) and some very nice applications like postler.
Anyhow, this time it got my attention because it's favored programming language seems to be vala. Surprise :)
A part of this effort is also to improve the programming experience by providing an - in loose words - integrated development environment - an editor (scratch + vala plugin) and build system (cmake). Nice.