Qlobe is a fascinating example of quine in Ruby, submitted by a member of the Ruby core team - Yusuke Endoh.
Programs that output changed executable versions of themselves while managing to spin the globe and still remaining executable are cool, right?
To experience its magic, run the following
curl -fSSl https://gist.githubusercontent.com/shime/f0ebe84ca42c33b51d42/raw/5e74315dc6b6fe572f8a457536ad7eb17ad3f1e4/qlobe.rb > qlobe.rb; while true; do ruby qlobe.rb | tee temp.rb; sleep 1; mv -f temp.rb qlobe.rb; done
This concept has also been ported to JavaScript, by Martin Kleppe. He has given a great talk named 1024+ Seconds of JS Wizardry on JSConf EU 2013.