Sniff network for iTunes #nowplaying mDNS announces via ngrep. Requires Ruby 1.9 for the awesome named-group regexes. Expand to do interesting things based on what you're playing.

nowplaying.rb

match = 'nowplaying'

ngrep_command = "ngrep -W byline '#{match}' port 5353"

puts "Watching network for iTunes mDNS #nowplaying announces..."

IO.popen(ngrep_command).each do |line|
  if line.match(/\##{match}/)
  	pattern = /nowplaying-title=(?<title>[\w ]+).+nowplaying-artist=(?<artist>[\w ]+).+nowplaying-album=(?<album>[\w ]+)/

  	nowplaying = pattern.match(line)

	puts
  	puts "Artist: #{nowplaying[:artist]}"
  	puts "Album: #{nowplaying[:album]}"
  	puts "Title: #{nowplaying[:title]}"
  end
end

true story