I've been thinking a bit about time travel today, and whilst I think overall travelling in time would be problematic (losing all narative structure to your life, requiring way too many tenses to keep track of and leading to constant jetlag) I think there are some things it could be really useful for.

Most useful would be the ability to transport objects in time - imagine getting home from work, putting a roast in the oven and setting it to start cooking 3 hours ago. Then making up an extra plate of food and transporting it to tomorrow's lunchtime so you can eat it freshly cooked and still hot. Food storage would also be revolutionised. Instead of trying to keep things fresh you just reach into the past to grab it when it actually was fresh! Leftovers would remain freshly cooked, you could have vine ripened summer tomatoes in the middle of winter and your milk would last however long you needed it to.