This is what I've been wondering: What expression of joy fits?
Take a look at the following video, change the setting, the characters, and the cause of celebration, and you will quickly get the drift - it is the mood of celebration and the satisfaction of being suddently liberated from something horrible that suits the day.
The Mayor of Munckin City is right: This is a day of independence for all of us and our descendents!! Let the joyous news be spread, the wicked administration at last has fled!!!!!!