In this scene from tomorrow's episode of Lost, "Jughead," we get to see Desmond and Penny's love child. Oh and Desmond explains to Penny why he needs to help go and rescue them.
Daniel: Do you have access to lead? Or concrete? You need to fill the crack with lead and bury it. Then everything will be fine. Ellie: How do you know that? Daniel: Because 50 years from now, this island is still here.