When something strikes you as funny, and you start giggling... and it becomes near impossible to stop. And when you do, the slighest thing can start it going again, making it very difficult to keep from doing it for any length of time.

It's odd, because a gigglefit doesn't have to start with something extremely funny. It may not even be very funny at all, enough to usually cause a chuckle and then you forget about it. But at the right time, you end up unable to prevent those giggles.

They always seem to occur at the totally wrong time. There's nothing worse than being somewhere where laughing or giggling is inappropriate, and you just can't help doing it...

I am prone to gigglefits...