We have some very odd shaped boxes that we have held on to for wrapping obvious gifts like DVDs or books. We have also been known to do scavenger hunts for gifts that cannot be wrapped. One year we got Mom an area rug she’d had her eye on, so we wrapped clues in little jewelry boxes and had her hunt for it. There was no way to wrap the rug. It was far too big.
The odd box thing backfired one year, when I accidentally put two items in the same box and wrapped an empty box. I don’t think my sister will let me forget that one, especially since she opened the empty gift first.