Right now the standard language to build Linux software is C, which is great for performance, but not great for development speed. There are ports of things like GTK+ to other languages, but ports are less supported and usually don't take full advantage of their language's unique flavor.
To maximize impact per unit of time spent developing open source software, and also perhaps to entice more people into contributing to open source software, I believe it would be a good idea to build a desktop environment/widget toolkit with an opinionated API in Ruby. Anyone who has experience writing Ruby on Rails code with an automated red-green-refactor cycle likely could testify that it is pleasant and fast. Why not bring that sort of experience to building desktop software?