The documentation at rdoc.rubyforge.org seems to be more complete than the version at rdoc.sourceforge.net (which incidentally has a 2003 modified date).
Also, there is a great source of examples: the Ruby core and stdlib documentation. For example, take a look at one of the class methods from the File
class:
File.atime(file_name) => time
Returns the last access time for the
named file as a Time object).
File.atime("testfile") #=> Wed Apr 09 08:51:48 CDT 2003
You can view the original source code, including the RDoc markup, by clicking on the first line (in the actual RDoc page, not in the quote I included in this answer). In this case, the method was implemented in C, but the RDoc formatting is the same as if it was implemented in Ruby:
/*
* call-seq:
* File.atime(file_name) => time
*
* Returns the last access time for the named file as a Time object).
*
* File.atime("testfile") #=> Wed Apr 09 08:51:48 CDT 2003
*
*/
From this you can see that call-seq:
lets you replace the method name and parameters with text of your choosing, which is very useful for class methods. It also shows how you can display example code in a monospaced font by indenting it, similar to Markdown.