BE ON YOUR BEST BEHAVIOR whenever a comedian's nearby, because if you do anything stupid, silly or even just a little bit odd, he'll put it in his act in a way that makes you look particularly foolish. And then everyone will find out what an idiot you really are.

If you're unlucky enough to be related to a comedian, there's no hope. You can't hide your stupidity all the time. In fact, you might as well start looking for a lawyer right now because soon the entire late-night television audience will hear exaggerated stories about the time you farted so loudly that your entire house collapsed.

Take, for instance, the person who had the misfortune to father comedian Jerry Seinfeld, veteran of The David Letterman Show and The Tonight Show and the featured performer last week at the just-opened comedy palace in Cambridge Catch A Rising Star, the Boston area branch of a well-known New York club.

So what that Jerry's dad puts his face in front of his car's exhaust pipe so that his eyes will look red and swollen when he moves the couch down-stairs? So what if dad reads books written by Ph.D.'s on how to pack car trunks just before the family goes on vacation? Does the whole world have to know?

For some strange reason, all three comedians performing on Sunday night felt the need to reveal all kinds of embarrassingly dirty family and personal secrets which made everyone laugh but were really disturbing if you sat down and thought about it over a cup of arsenic-laden coffee. That is, unless they were lying, but comedians don't lie. Do they?

Gary Lazar, another nationally-known comedian and MC for the evening at The Catch, told the audience about his serious problem with hallucinogenic drugs. It seems Gary thinks his parrot escaped one day from its cage, tied him up, and said, "Now you repeat what I say!" And Paul Kozlowski, winner of a Boston-area comedy contest and Sunday's third performer, let us know that his entire family is inbred. Now I personally don't care if all of Cambridge knows that his mom is also his aunt, but maybe his father--I mean uncle--does.

It's possible that the basement club's old-fashioned, cozy setting tricked the three comedians into thinking they could make these embarrassing revelations without anyone passing them on to outsiders--like I'm doing right now. Standing in front of a row of shelves lined with fake books, the performers were close enough to the tables to smell the odor of two-dollar drafts on the audience's breath.

Or perhaps the performers became so confused at the inexplicable wooden signs on the walls that they forgot their other jokes. These strange-looking notices made vague references to theatricals, agents, children and pets which none of the agents, children or pets around me could understand. (There were no theatricals around to be consulted, although a hippopotamus hiding under an ash tray was also perplexed.)

To be fair, the comedians also cracked some less offensive jokes. Jerry talked about elderly residents of Florida who drive with their faces at the level of the dashboard radio, lights blinking an "eventual left turn" signal and car moving at 10 m.p.h. so they can relish every moment of the trip. He also talked about the type of pig that produces the pepper-filled luncheon meat on display at your neighborhood supermarket.

Nor did Harvard students escape the humorous wrath of Jerry. It seems he spent an afternoon running about the Yard, telling book-toting students, "I know you have to work, but I thought I'd just let you know that I'm going to get some pizza." Jerry boasted, "I'm proud that I don't know what the Treaty of Versailles is."

While the other comedians were performing, Gary Lazar stood near the bar barely laughing. I guess even the funniest joke becomes stale after you've heard it ten times in a week. Come to think of it, it's amazing the comedians are able to laugh at their own jokes.

The friend who accompanied me to the show saw both Jerry and Gary at The Catch in New York City during winter vacation. They were telling most of the same jokes back then.

When, at the end of Jerry's spiel, I approached Gary, he assured me that he had enjoyed his first visit to Cambridge, although he wishes people up here would learn how to walk better. It seems he and Jerry were walking through the Square when a woman right in front of them slipped on the ice and fell. "Don't you feel foolish," Gary said, as he began helping the woman to her feet. But as he said this, he himself slipped and landed in a puddle of ice-cold water. "Not as foolish as you must feel," the woman responded.

I almost told him about my own recent spill on the ice, but I had visions of the entire city of Los Angeles finding out about my little mistake. I could hear Gary saying, "I was walking in Cambridge last week and this Harvard kid, who looked about as coordinated as a stalagmite, slipped on the ice, flipped six times, and swan dived into the wind-shield of a passing bus." So I cautiously kept my mouth shut.

Gary and Jerry performed at The Catch for the opening week only and will now return to their families to get more material for their acts. Paul Kozlowski, however, will return to the scene every Sunday night to imitate the sound of a cat falling from a helicopter and landing on asphalt.

But Gary said he wants to return to the Boston area during baseball season so he can go see the Boston Red Sox lose a game. "I'm a Mets fan," he whispered into my ear so no shotgun-toting Bostonian would hear.