Thank you gift

What's a good thank you gift to a friend of mine for unexpectedly watching my kids overnight and driving them to school the next day when I went into labor and my two designated "Angela is in labor people", my sister AND back up friend, were both out of town?! I had my son 2 weeks early, and they were both gone for only 2 days, but of course I had him during that time! Lol. It was so last minute, and I want to thank her and her husband in a nice way. Ideas?