Do they already have a place to live? If they both work, maybe a gift certificate for maid service for a month?
Gift certificates to restaurants that could be used at the end of a busy week.
Is there some item that they've always talked about but they would never buy for themselves for one reason or another?
Are they going on a honeymoon? Maybe you could stalk the frig for them for their return?
Homemade desserts for a month, maybe.