Probably most interesting to the people here is the quine relay: https://github.com/mame/quine-relay ("a Ruby program that generates a Rust program that generates a Scala program that generates ...(through 128 languages in total)... a REXX program that generates the original Ruby code again")
Also around 6:50 he shows a nice little easter egg in the quine of a RubyConf talk by Yusuke Endoh (mame). The talk is also full of really nice examples: https://www.youtube.com/watch?v=VDk---TgCv4