名前空間を取り除いたクラス名を取得する ref: http://qiita.com/uchiko/items/96f5ba10538bce99737a

pry

[1] pry(main)> show-source Class.class_name

From: /Users/uchiko/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/yard-0.8.7.6/lib/yard/core_ext/module.rb @ line 7:
Owner: Module
Visibility: public
Number of lines: 3

def class_name
  name.split("::").last
end
[2] pry(main)>

sample.rb

module Hoge
  class Fuga
    def name
      self.fullname.split('::').last
    end

    def fullname
      self.class.to_s
    end
  end
end

m = Hoge::Fuga.new
p m.name     #=> "Fuga"
p m.fullname #=> "Hoge::Fuga"