The Giggle Loop is a theory of Jeff Murdock's, from the popular British sitcom Coupling. It is a feedback loop of laughter. As Jeff says, "To know about the Giggle Loop is to become part of the Giggle Loop."
The Giggle Loop is as follows:
1. You're in a solemn occasion, such as, say, a graduation ceremony, a formal dinner, or a minute's silence at a funeral.
2. You suddenly, for no reason, think that the worst thing to do in this situation would be to laugh, and as soon as you do, you almost do laugh.
3. You control yourself with deep breathing, and manage to not laugh.
4. You then reflect on how awful it would have been if you had laughed, and very nearly do laugh again.
5. The process repeats several times, as you attempt to prevent your laughter, which has acquired monumentous inertia by now, from escaping.
6. To your horror, you find this situation funny.
The Giggle Loop was illustrated on the sitcom with the aid of a stack comprising several beer glasses. Sooner or later, the glasses must fall.