I was at a Walmart I don't normally shop at, near my mom's house, and the oddest thing happened. All the lights in the store dimmed and all the lights in the dairy cases, fridges and freezers shut off. At first I thought maybe there had been a power failure and a generator was keeping the main lights on, but dimmed. But then I overheard a woman telling her husband that this is part of an energy saving program and the lights do this every hour or so and it lasts about 5-10 mins. They did come back on normally after about that long, but I was shopping in the grocery section while this was going on and it was very annoying that there were no lights on in the fridges and freezers! I'm glad my Walmart doesn't do this - or if they do it has never happened when I was in the store.