There was a Haml-like language called GHRML a while back, but it seems to have disappeared. There is something like it called SHPAML: http://shpaml.webfactional.com/
Though I think Ruby has better markup libraries in general. For example, they have Nokogiri, which is an absolute joy to use for XML parsing. And implementations of Markdown and Textile with actual parsers, whereas Python Markdown and Python Textile are straight regex-using ports of the Perl/PHP versions. It's kinda sad really.
To learn Ruby I decided to redo my website in it, and I felt the complete opposite. I was surprised there's nothing comparable in the Ruby world to Jinja2 or Mako. Nothing supports blocks/macros or template inheritance, so I wrote my own small template engine in Ruby that does.
python-markdown is in no way port of perl version. It's complete parser which can be extended and so on. But python-markdown2 is port of perl version, based on regexps instead of being real parser.
Though I think Ruby has better markup libraries in general. For example, they have Nokogiri, which is an absolute joy to use for XML parsing. And implementations of Markdown and Textile with actual parsers, whereas Python Markdown and Python Textile are straight regex-using ports of the Perl/PHP versions. It's kinda sad really.