I'm sad that this is the solution.

gistfile1.txt

 class Log1Buffer < ::Array
    for meth in PUBLIC_METHODS = %w(debug info warn error fatal).map(&:to_sym)
      eval "define_method(:#{meth}){|*a| push [:#{meth}, *a] }"
    end
  end
1.9.3p194 :062 > buffer.debug "something"
 => [[:fatal, "something"]] 


 class Log2Buffer < ::Array
    define_method(:debug){|*a| push [:debug, *a] }
    define_method(:info){|*a| push [:info, *a] }
    define_method(:warn){|*a| push [:warn, *a] }
    define_method(:error){|*a| push [:error, *a] }
    define_method(:fatal){|*a| push [:fatal, *a] }
  end
* works as expected