A simple bot that manually retweets haikus directed at it. Uses the Twitter gem. You will need to provide the appropriate API tokens.

haiku_bot_example.rb

require 'rubygems'
require 'twitter'
require 'time'

@blacklist = []

def log text
  @logfile.write( "\r\n" + Time.new.to_s + ": " + text.to_s())
end

@logfile = File.new('haiku_log.txt', "a")

log("starting!")

regex_url = /((https?|ftp|gopher|telnet|file|notes|ms-help):((\/\/)|(\\\\))[\w\d:#%\/;$()~_?\+\-=\\\.&]*)/i


def get_last_response_time
  last_time = nil
  begin
    f = File.new('haiku_last_response_time.txt', "r")
    last_time = Time.parse(f.read)
    f.close
  rescue
    #just don't choke
  end
  
  last_time
end

def set_last_response_time last_time
  #no error handling because we want it to succeed
  f = File.new('haiku_last_response_time.txt', "w")
  f.write(last_time.to_s)
  f.close
end

Twitter.configure do |config|
  config.consumer_key = 'CONSUMER_KEY'
  config.consumer_secret = 'CONSUMER_SECRET'
  config.oauth_token = 'OAUTH_TOKEN'
  config.oauth_token_secret = 'OAUTH_TOKEN_SECRET'
end

last_reply_response = get_last_response_time()
#puts "last response time: #{last_reply_response}"

#while true
  #puts Time.new.to_s + ": Getting replies..."
  begin
    replies = Twitter.mentions
  rescue Exception => err
    puts err
    log(err)
    exit
  end
  #get relevant replies
  replies.reverse!
  replies.reject!{|reply| reply.created_at <= last_reply_response } if last_reply_response
  #puts "...got #{replies.length} replies."
  
  last_time = nil
  replies.each do |reply|
    shouldtweet = true
#    log(reply)
    
    #check if user is blacklisted.
    if (@blacklist.member? reply.user.screen_name.downcase) then
      shouldtweet = false
    end
    
    # check if tweet is a mention - not for retweeting
	# use \A instead of ^ - some tricky bots use line breaks inside tweets.
	# http://www.regular-expressions.info/anchors.html#az
    if (reply.text.strip =~ /\A@haikutime/i).nil? then
      shouldtweet = false
    end
    
    #If shouldn't tweet, skip the retweeting, but still mark this as the last response (so we don't have to deal with it again).
    if (shouldtweet) then
      #remove any mentions (including mention of "@haikutime"), remove any hashtags
      log("about to tweet: " + reply.text)
      replytext = "from @" + reply.user.screen_name + ":" + (reply.text.gsub(/@\w+/i, "")).gsub(/#\w+/i,"").gsub(regex_url, "")
      log("cleaned tweet: " + replytext)
      begin
        Twitter.update(replytext)
      rescue Exception => err2
	puts err2
	log(err2)
        sleep 60
        next
      end
    end

    #puts "posted response: #{replytext} "
    last_time = reply.created_at
  end

  if last_time
    set_last_response_time(last_time)
    last_reply_response = last_time
  end
  
@logfile.close

I had an SSL issue on my computer, solved using:
http://stackoverflow.com/a/16134586/359362