I prefer my readmes in plain text formats, be it Markdown, AsciiDoc, or unstructured txt. This reminds me of two interesting projects, maid[0], a task runner that uses markdown files, and mandown[1], a markdown pager that improves reading markdown files in the terminal.

[0]: https://github.com/egoist/maid

[1]: https://github.com/Titor8115/mandown