What to do when you have a grumpy child?
I try my best to ignore them when they are in a bad mood for no reason. Mostly they want to be picked up, have cuddles and have their own way with everything. But having two children - you just can't do that! Otherwise you will get yourself stuck in a place where you will not be able to do anything yourself. I tend to go to the kitchen and do some cleaning there or in the dining room.
Get on with what you are doing
Don't stop what you're doing, just carry on and they will soon realise that being grumpy and moody will not get them what they want! May take hours for them to settle but it will be worth it.
Maybe it's nap time for them. Even if they don't usually take a nap, try them out too see if they will. If not, then atleast you tried.
Go out for a walk
Maybe they're bored. Go out for a walk. Calm yourself down and it will also calm the kids down too! Works wonders. I used to do this all the time when the weather was nice.