libRocket (http://librocket.com) is a renderer agnostic XHTML/CSS renderer, useful for creating UIs for games and the like. Hopefully makes assembling a game UI a breeze.
Advantages of v8rocket:
Renderer agnostic, input agnostic, allows a fully dynamic layout, that can grow/shrink etc. as needed, uses existing layout technology - standardized XHTML/CSS to describe layout, allows easy "theming" via CSS, or even changing the XHTML, without having to recompile, allows delegation of UI work to developers skilled in web programming.