A "ruby method describer"--this gem allows you to introspect methods while within irb or ruby-debug.  It reveals everything conceivably known about that method.  This includes source, ri, arity, rdoc comments (on 1.9), etc. etc.

For me it has proved quite useful, and I wouldn't leave home without it [try it--you might really like it].

Examples:
>>
 class A; 
    def go(a); end; 
  end
>> A.desc_method :go
   # it outputs everything it knows about it...arity, source, RI, etc.
ri for A#go
Nothing known about A
(end ri)
#<UnboundMethod: A#go>     arity: 1
A#go a
proc { |a|
  # do nothing
}

an example in 1.9:
>> File.desc_method :delete
ri for File.delete
----------------------------------------------------------- File::delete
     File.delete(file_name, ...)  => integer
     File.unlink(file_name, ...)  => integer

     From Ruby 1.9.1
------------------------------------------------------------------------
     Deletes the named files, returning the number of names passed as
     arguments. Raises an exception on any error. See also +Dir::rmdir+.

(end ri)
#<Method: File.delete>     arity: -1
appears to be a c method
#parameters signature: delete( [[:rest]] )

========= Installation/usage:=====
Installation:
$ gem install rogerdpack-desc_method
Usage:
>> require 'desc_method'
>> Class.desc_method :method_name # class or instance method name
...
>> instance.desc_method :instance_method_name
...

other goodies also included:
Class.desc_class  method # outputs descriptive information about that class--ex:
>> Object.desc_class
# outputs RI, methods, etc.
or 
>> Object.desc_class :verbose => true
# outputs RI, method lists including inherited methods, ancestors, constants

Kernel#method is monkey patched to output a "separator" between its inherited and non inherited methods--i.e.
>> method
=> [:first, :second, :after_this_are_inherited>>>>>, :some_inherited_method, :another_inherited_method] # adds in the separator


This gem wraps (in a very convenient way) functionality provided by Method#source_location, ruby2ruby, etc. Also thanks to manvenu for some original code inspiration, SourceRef (MBARI), and ruby-debug, who made this possible. Thanks guys!

Comments/suggestions welcome rogerdpack on gmail or github