Ryan Leavengood:
> def cheer(name)
>    puts "Hurray for #{name}!"
> end
> 
> 3.times do cheer('David') end

I'd prefer:

class IO
  def cheer(person, times = 3)
    self.puts 'Hurray' + (times ? ', hurray' * (times-1) : '') + ' for ' +
      if person.is_a? Rubyist and person.respond_to? :nickname
        person.nickname
      else
        person
      end + '!'
  end
end

module Kernel
  def cheer(*args, &block)
    $defout.cheer(*args, &block)
  end
end

Malte