Infant Sorrow is a fictional band created by Russel Brand, or Aldous Snow in the band, for the Movie "Forgetting Sarah Marshal." Also used in "Get Him to the Greek." It uses funny lyrics like "When life slips you a Jeffery, Stroke furry wall" referring to Get Him to the Greek when the main character has smoked a Jeffery and is think he has a heart attack and is told to stroke a furry wall to calm him down, which does not help.
Dude 1: Bro, you see Get Him to the Greek?!
Dude 2: Yeah dude! Awesome movie.
Dude 1: Infant Sorrow is the funniest man ever!
Dude 2: You mean Russel Brand right?
Dude 1: Yeah!