In addition to white noise machines, here are some excellent tools of mommyhood that I've picked up along the way:
CamelBak water bottles for kids & mommies make everyone happier. Staying hydrated, especially in hot weather, always makes us feel better! Plus, they don't leak or break, and for some reason I drink way more water out of this than out of a cup. I will warn you - be sure to wash it every once in awhile, even if it just holds water. The silicone spout can get mildewy after awhile. (Ask me how I know.)
Whole carrots (not the baby kind) have been great for baby S to chew on during dinner - especially when we're out and need something to occupy him for awhile. He's pretty good about just shaving off slivers with his tiny teeth, but I still keep a close eye on him just in case. Now when I get the carrots out of the fridge, S crawls over to me and starts to whine for one! Atta boy.
Silicone kitchen utensils make great toys. They are fairly indestructible, I don't mind if baby chews on them, and they're easy to hold. You do get some funny looks when you bring a whisk out in public, though. :)
Apps like Disney Junior, Jake's Pirate School, Monkey Math, Cut the Rope, and ABC tracing can be lifesavers during hectic times. I usually let my 3-year-old play on my phone while I make dinner to maintain some sort of sanity while baby is whining and pots are overflowing. ;)
Buckets & plastic gloves make for an excellent trash/treasure hunt outside. The toddler gets excited about piratey things these days, so treasure hunts are right up his alley. We enjoy finding bits of moss and fungus, unique rocks, and flowers - and also do our duty to keep our neighborhood clean at the same time!
Music. I don't know how many times an upbeat song has turned a rough day around. J loves "I will Find You" by Jimmy Needham, and "Boat Song" by JJ Heller. We also like to make up silly songs like "Macaroni and Hungry Pickles" to the tune of "Are you Sleeping?"
What are your tools of the trade? How do you turn around a rough day with kiddos?