Getting out of the house periodically is helpful....both alone and with the kids. Sometimes I find getting out of the house - even just going to the mall to let them run around for an hour in the play area - can make a huge difference for all of us on the worse days. You feel like getting out of the house is going to send you through the roof, but once out, it helps me gain perspective and relax a bit. You can't go out expecting to run errands or really get anything done, but just getting all of you get a change of scenery and if possible, let the kids run around and burn off steam. Afterwards, mine are usually more mellow and are ready to take nice naps which gives you a period of time to chill out in peace at home.
Our family had a couple crazy weeks and were feeling crazed. We dropped the kids off to grandma for maybe 1-2 hours and went to Panera for a quick quiet dinner. It was grown up food, quiet, and it did wonders for our sanity. Even though it was a short time, it helped greatly. It was during one of those crazy cold spells and we hadn't been going out of the house unless necessary so the kids really benefitted from getting out of our house as well and playing at grandma's house.