I read that you don't want to go and buy them something--(assuming you already have fabric, batting, etc. in your house, there is less money out of pocket, right)--so I say a Christmas lap quilt for the couch or tree skirt. or Christmas placemat set and/napkins,
But a nice placemat and napkins set just doesn't seem to go with paper plates and throw away cups, which many younger couples are using these days! !!!!
So, I'd opt for the Christmas quilt--assuming they celebrate Christmas.