From out of murky depths of the Lafcadio codebase, I bring you a tiny utility library called Ruby Month. It’s a modest thing, intended to make month-level manipulations easier. For example:

require 'month'
jun2005 = Month.new( 2005, 6 )
jun2005.to_s                             # => "Jun 2005" 
jun2005.start_date.to_s                  # => "2005-06-01" 
jun2005.end_date.to_s                    # => "2005-06-30" 

jul2005 = jun2005.next
jul2005.to_s                             # => "Jul 2005" 
may2005 = jun2005.prev
may2005.to_s                             # => "May 2005" 

to_sort = [ jul2005, may2005, jun2005 ]
to_sort.join ', '                        # => "Jul 2005, May 2005, Jun 2005" 
to_sort.sort!
to_sort.join ', '                        # => "May 2005, Jun 2005, Jul 2005"