My wife has a favorite game. Perhaps you've played it before.
Take 45-50 cds and jewel cases. Remove two cds from their respective jewel cases and swap them so that cd "A" is in jewel case "B". Repeat for all 50 cds.
For you true pros out there (like Merrin), you can play this game with 200 or more cds! I think the current record is swapping out over 230 cds & cases, but I wouldn't know. Like I said, my wife is the pro!