Today, I was showing a friend of mine some of the works of Terrible Writing Advice, and during the episode on Dark Lords, we had a brief discussion about Macguffins (plot devices).
During the discussion, he remarked about it would be funny to see a villain that collected Macguffins and displayed them in a kind of museum, perhaps taking the heroes on a brief walking tour of it before the final confrontation. and in this room is our collection "Things that can end my reign of terror", not to be confused with "The last hopes of mankind"...
It seemed like a neat idea; overpower your villain, but then fill the confrontation room with items that bring him back into balance. For example, the room might have a basin that inverts the effects of liquids so that a healing potion deals damage or a strength draining potion steadily makes you stronger. Another might be a gemstone that absorbs magical attacks or shield that attracts the strikes.
While I loved this idea, I had a more narrative focused idea that would be awesome to explore, but probably not go over well with the players.
The players should have to have quested after a Macguffin in order to help them defeat the Dark Lord and when they enter his castle they need to cross The Hall of Macguffins. To the ignorant, it might just seem like an exhibit of random items ranging from war glaives to rubber ducks. Some knowledge checks might reveal that some of these items are devices of rumored magical power thought lost. Approaching the Dark Lord for the final conflict, they raise the Macguffin up to use and the Lord simply bursts out laughing. He would then explain that for years he had been tricking adventurer's into believing that there was some magical item that could end his reign once and for all only for it to be a rumor he himself had started. When they were resolutely trounced, that item would be added to the collection.
I do not intend to DM any time soon, but the concept of a Hall of Macguffins is one that I'll probably come back to.