In B/W, I was surprised that underneath the grounds of the Pokémon League is the castle of N! (How did the castle go there anyway? :-o) I pretty much liked the cutscene where N's castle unearthed itself. It looked and felt so A-MAZING! (N's room is still creepy to me though, as always.) Almost like it is the right place to end the story, rather than the usual, where you beat the champion, go to the Hall of Fame and then you're done.
I haven't visited N's castle in my White 2 yet, but I've seen some pics of it, and I see that it's wrecked. Still though, adds up more to the adventure. :D