Just when did Aunt May’s leftover marshmallow yams hit the refrigerator shelf? Keep track of the barrage of holiday leftovers with the DaysAgo Digital Day Counter ($10 for a pack of two, howmanydaysago.com). The reusable counter keeps track up to 99 days and attaches to a variety of surfaces—so you’ll know just how many turkey sandwiches you still have to eat before it’s time to toss the bird.