With the amount of alcohol that's in my blood, I'm open to any suggestions tonight.
Option 1:
Don't do anything in particular. Stay cool and laid back.
Trust in humanity and hope that people will stop acting like arseholes.
BnB's fine, anyways. Everybody's overreacting for no reason.
Option 2:
React more quickly.
Whenever you see that a thread is about to be ruined, isolate the people who are responsible and go Terminator on them.

Option 3:
Be cold, be calculating, be evil.
After a thread is ruined, go analyze the remains, find out who did this and give him/them a public warning.
After 3 warnings, give them a 24-hour ban. After that, it's zero tolerance. Next offence will lead to a 48-hour ban, next offence after that leads to a permanent ban.
That'll teach the fuck.
Option 4:
Give us an "ignore user" button. Job done.
That'll save the board, the trees, the polar bears and even the ozone layer. Yes, please give us the magical button.
Option 5:
Please teach us how to behave on a message board. Give us lessons on how to be polite, how to be respectful and how not to ruin every single thread we step into.
Then rate us: At the end of every month, the best BnB member will get some kind of gold medal on his avatar, and the worst will get a "I am not internet-smart" avatar and a 1-week ban.
That's a novel idea, but it just might work.
Option 6:
[Insert other irrational behaviour pattern here.]
(Diplomacy, tolerance and other shit like that...)
And no, banning one particular member just because you don't like him doesn't work. So you're gonna have to come up with better stuff, folks.