Having a witty one-liner to slip into their diatribe will help dissolve any tension and relax everyone involved. The use of humor in even the most serious arguments is absolutely necessary. Arguments should be fun as well as challenging in a non-arrogant intellectual sense. There seems to be a popular misconception that humor and emotion have no place in adversarial proceedings. I think it is spread by a few of those who consider themselves professional debaters but just aren't funny and want to slant the rules in their favor.
Human arguments involve emotion.
Good human arguments also involve zany one-liners. Note that the use of humor in no way trivializes the issues involved. Any issue I can think of worth arguing over involves a group with more power doing something wrong. My personal style inevitably centers around poking fun at this group. Another safe target is yourself.