WE have a book at work called "What Are You So Grumpy About?" It is a kids book about feelings.
We pass it around on occasion to gently remind others of their mood, but more often the grumpy one of us asks where the book is, places it on his/her desk for the day and tries to read it before the end of the day. When it is on my desk it helps me to be gentle with myself about my grumpiness, and it allows others to not to have to take me so seriously.
I agree with all of the above posts too. I am learning meditation and that helps also.
Finally judging the feeling ALWAYS makes it worse for me, and harder to not stay stuck in it.