Tom Keary answered his jury duty summons the same way that dozens of other District residents did Wednesday, arriving at D.C. Superior Court at 8 a.m.

It wasn’t until a clerk called him and about 40 other prospective jurors to a courtroom that things took an unusual turn: The trial, for felony assault, was before Judge Ann O’Regan Keary, his wife of nearly 40 years.

It’s common for judges to see friends, neighbors or colleagues in their courtrooms, and they are generally dismissed to avoid conflicts of interest. But this was the first time a judge’s spouse was part of a jury pool in his or her courtroom, said court administrators.

What are the odds? The jury pool includes about 18,000 District residents each month, and only about 37 judges hold jury trials in Superior Court’s civil and criminal division.

Judge Keary had driven her husband, a 63-year-old civil rights lawyer, to the courthouse, and they parted ways upon arrival. “I joked with him and said, ‘Wouldn’t it be funny if you got picked for my courtroom?’ ” she said. “When I got the list of prospective jurors called for my case, there he was.”

When he walked into the courtroom and saw his wife on the bench, Tom Keary said, the two smiled at each other as he took his seat in the gallery.

On a form that asked whether he knew anyone involved in the case, he circled “Yes.”

When the attorneys called him to the bench for an interview, the juror and the judge told them they were husband and wife.

Then the judge dismissed him. His service wasn’t complete, however: She reminded him he had to return to the waiting area to see if he would be called to another trial.

“I poured him right back into the pool immediately,” the judge said.

Three hours later, Keary and the other prospective jurors were released. “We laughed about it when we got home,” he said.