Caper

Verb: skip or dance about in a playful or lively way.
Noun: 1. A playful skipping movement. 2. An illicit or ridiculous activity or escapade.
Origin: from the Latin capreolus - 'little goat'

Even the Victorians enjoyed capering. This scene is possibly inappropriate though: she just told him his mother-in-law died.

This is a great word when it doesn't refer to 'a flower bud of a southern European shrub, pickled for use in cooking' (They are small and green and don't taste very nice).
To caper, on the other hand, is a brilliant action, one which we should all do more often, even if it is in private. I know I do (when there is no-one around to laugh at me). The word brings to mind young lambs, goats and, perhaps to a lesser extent, Gollum from The Lord of the Rings. I think I like it because of its uncontrolled nature: I see it as something that happens when you are so happy that there is no other way to express yourself.
Always be suspicious of those who express their happiness through song or dance or some other fancy action, it's just not natural and they probably aren't overjoyed, they are just showing off. We all know that if you are truly, uncontrollably happy then the only option is to hop from foot to foot while waving your arms above your head, moving quickly around the room (or street). Luckily there is a word for this: capering.
P.S. A word derived from the Latin for 'little goat'? Excellent.