Another solution to this post (http://jumpstartlab.com/news/archives/2013/04/23/the-death-of-ifs) with objects that can do real stuff, like Twitter (or any other social network, i.e.) API calls.

death_of_ifs.rb

def start
  command = ""
  command_processor = CommandProcessor.new
  command_processor.add_command('follow', Proc.new { puts 'do some stuff' })
  while command != "q"
    printf "enter command: "
    command = gets.chomp
    command_processor.process(command)
  end
end
 
class CommandProcessor
  def initialize
    @commands = Hash.new
    @commands[:q] = Proc.new { "Goodbye" }
    @commands[:tweet] = Proc.new { "tweeting" }
    @commands[:dm] = Proc.new { "direct messaging" }
    @commands[:help] = Proc.new { "helping" }
  end
 
  def add_command(command, output)
    @commands[command.to_sym] = output
  end
 
  def process(input)
    (@commands[input.to_sym] || Proc.new {} ).call
  end
end