class Notifier
  @@prefixes = {
      :done => "[+] ",
      :note => "[!] ",
      :error => "[-] ",
  }

  def self.method_missing(method, *args)
    puts "#{@@prefixes[method]} #{args}"
  end
end

# then you do like this all over the place
Notifier.done "This thing was completed now."
Notifier.error "ZOMG!"