Episode 12(The Space Probe Disintegration) from season 8 was aired on 8 January 2015 had some very funny and special moments. My personal favorite was when Leonard and Sheldon started crying all of a sudden. Here are 12 Best moments from The Big Bang Theory-The Space Probe Disintegration episode..
#12 You Want To Be Green?
So the Episode starts with Penny and Amy both unhappy over how they have to watch all the stupid shows guys like, play geeky games with them and requests Sheldon and Leonard to do something Penny and Amy want at least once. On response to which Sheldon says You want to be green? Hilarious moment :D