SLiP is a quick, alternative syntax for creating and editing XML data by hand and if you know Python, it should also be familiar. not my cup of tea but has a nice comparison of other lightweight xml notations
Haml takes your gross, ugly templates and replaces them with veritable Haiku. Haml is the next step in generating views in your Rails application. Haml is a refreshing take that is meant to free us from the shitty templating languages we have gotten used to. Haml is based on one primary principal. Markup should be beautiful. Haml is a real solution to a real problem. Stop using the slow, repetitive, and annoying templates that you don’t even know how much you hate yet
PXSL – Parsimonious XML Shorthand Language PXSL ("pixel") is a convenient shorthand for writing markup-heavy XML documents. It provides XML authors and programmers with a simple, concise syntax that they can use to create XML documents. For more advanced users, PXSL offers customizable shortcuts and sophisticated refactoring tools like functional macros that can markedly reduce the size and complexity of markup-dense XML documents. The short version is this: PXSL is XML turned inside-out. Instead of tagging the structure, you tag the non-structure, which is the better approach when most of your information is structure.