This episode was hilarious! I think this time I'm just going to list some favourite moments:
The brotherly banter in the beginning of the episode.
Dean's view of Sam: "blahblahblahbla..."
"They probed.. again and again and again and again... But that was not the worst part"... "They made me slow dance!" *ROFL* The look on Dean's face when he hears this is priceless :D.
Then Sam being all emo and empathetic, "You brave little soldier, this must be so hard for you. I acknowledge your pain", etc. and then hugging the UFO guy's roommate.
I really wonder how many takes they had to do while filming the episode, because it must have been incredible hard to keep a straight face through some of that stuff *g*.