I remember having the idea for a refrigerator that scanned the barcodes of any items inserted or removed from it. If a carton of milk, for example was removed and not replaced, the refrigerator would add it to the grocery list. If an item stayed in the fridge for longer than a certain period of time, the fridge would alert you to possible expiration. There would also be a feature that would give you recipes you could cook using items in your fridge. I'm still waiting for something like that to come along.