Twice a month a diverse collection of divorced fathers and mothers who have consistently failed to make regular child-support payments are called before a Montgomery Circuit Court judge in Rockville to explain why they should not be thrown in jail.

The pageant of wheedling, mumbling, last minute bargaining and tall-tale telling that ensues during these court sessions is known as Contempt Day. Yesterday was one such day.

It offered an education in extenuating circumstances as parents in arrears told why they had to flout or hadn't really flouted the child support programs prescribed by the court when families disintegrate.

"I've been trying to get a business tarted for five years," offered one Silver Spring father who had fallen more than $2,000 behind in child-support payments. But why hadn't he showed up in court last fall? "I didn't see my name on the docket," he explained.

Judge William Cave, who as a recently installed judge usually gets assigned Contempt Day, was not convinced and sentenced the man to 90 days in the Montgomery Detention Center for contempt of court.

The bailiffs closed in on the father, snapped the handcuffs on and took him away. It had a chastening effect on the 35 people waiting yesterday in Courtroom Six to plead their cases.

The Montgomery Circuit Court, which acts as a collection and enforcement agency through its Family Services Division, carries more than 9,000 child support and other payments cases, but more than half of the people let their obligations slide.

"In normal times we're collecting over $2 million with an arrearage of $3.7 million," said Court Clerk Howard Smith. With a recession, he said, we could be collecting even less."

On contempt day, the dockets can run as high as 100, as it did a week ago Friday when a line of parents in arrears stretched into the hall.

Kramer vs. Kramer notwithstanding, nearly all of the parents before the court are men, and some of them are notorious.

"One man has four paternity suits against him, all in the same neighborhood," said June Nichols of the Family Services Division of the court, which from experience has learned not to accept personal checks. "He'll never be able to get married, he won't have enough money."

"Some of these guys are real smooth talkers with totally believable sob stories," State's Attorney Peggy Oidick said. But the only reason some gambits work is that the defendant happens to be appearing for the first time.

"I had an emergency with my car which I needed to take my little daughter to kindergarten," said one Silver Spring man. "I had to get a loan."

That excuse isn't good enough," said Judge Cave. "But I'm not going to hold you in contempt since you haven't been before me before. But don't come back again before me."

One Gaithersburg man took the witness stand, and in his own defense for not paying $1,160 to his wife for their children, pulled out a list of bills he had paid, including a pink slip for work on his truck.

"Oh," he said as the deputy sheriffs handcuffed him and led him off to the Detention Center.

Last summer one debt-heavy parent lunged at Judge Cave when sentenced to jail, and it took three deputy sheiffs to restain the enraged father.

"It's very depressing to deal with these cases," Nichols said. "There's so much spite. A woman sees a man buy a new car and all of a sudden she wants an increase."

Along with the spite, there's ambivalence. Some women can't cut old allegiances no matter how much of a rascal their ex-husbands might be.

Rosemary Ross, an attorney in the child support unit, had argued compellingly that one mad had defaulted on his payments long enough, when his ex-wife, who was in the courtroom and really needed the child-support money, turned to her with tears in her eyes.

"I don't want him to go to jail," she said," Ross recalled. "I could'a hit her. She got me all worked up."