Shopping, cooking, taking lunch/dinner with you when you visit, sticking the washing in the machine, hanging it up, washing up, mopping the kitchen floor, vacuuming, making cups of tea, fetching whatever from upstairs, basically anything a dd would be doing if she wasn't holding/feeding new baby and feeling sore because of stitches.
Of course I'm talking a dd here, rather than a DiL (though it may be equally all right) and only when you know for certain that whatever you do will be welcomed, and not seen as interfering/instrusive and likely to result in one of those I-hate-my-MiL posts on Mumsnet.