Later that night my friend told me about the hot tub. She said it had been around for years and at first there was no gate. But then a few incidents happened. Negative things, like drugs or violence. So a gate was installed with a code. The code was then given out to only a few long time users of the hot tub. They in turn shared the code with close friends they trusted. Eventually the code would spread over the years and something negative would happen. Then the code would be changed again. This had happened a few times in my friends long experience with the tub.
I took this over to email mailing lists and thus we have "hot tubbing".
When a list gets too big, has too many flames, and won't respond to cries for sanity from it's core members, hot tub it by doing this:
1. Send out a well subject headered message saying something like: "in 24 hours this list will end. A new list will start up. The new lists' address will be given out at local meetings in person only. If you want to start your own local list, please do so. We are sorry for the this but this list can no longer support the number of people on it."
2. Kill the list.
3. Start a new one.
4. Give out the address at an in person meeting.
5. Your core group will immediately subscribe to the new list and email out their close friends the new address. In a few months you'll have a good list again, albeit much smaller.
Note that the point at which a lot of school teachers know about the hot tub is usually close to the point where the code needs to be changed. Also, reading the whole post makes the hot tub analogy more memorable.