When developers release expansion packs, it often seems like they're just trying to continue milking an old title for some new money. With Hordes of the Underdark, Bioware's second expansion for their Dungeons and Dragons-based RPG Neverwinter Nights, you might be temped to think they are likewise trying to squeeze some cash out of an older title, but you'd be wrong, as Hordes of the Underdark is actually an enjoyable expansion that adds some new and interesting gameplay to the aging NN license.