Other than filling the garage and the driveway and the dining room with stuff, we're finding all kinds of weird things, like a toebreaker* of a book (Rifles of the World), but the biggie is the Horn of Gondor.
This is a genuine cow horn with a mouthpiece on the end. Mom, Dad and I think my brother bought it on a trip out west when we were teenagers. It's in excellent shape.
Naturally, my dad demonstrated it once for the kids, who then proceeded to make the rafters ring for the next 30 minutes.
"No, it's my turn, let me do it!"
It occurred to me that if we didn't have to return this to my brother, I could buy the LOTR costume pattern pack and make Legolas and Boromir outfits (and buy a bunch of stubble to glue to Imp's face, and a wig). After all, Boromir got a truly excellent death scene in the movie, but more importantly, he's the one with the Horn of Gondor.
As it is, it'll have to return to my brother's care, and I'm guessing he completely forgot its existence also. But that might not be a bad thing, because how much hornblowing can one household take?
*toebreaker book - so big and heavy that if you drop it on your toe, broken bones may result.