CHICAGO — Barack Obama, former leader of the free world and current Illinois taxpayer, returned home on Wednesday for that most somber of civic obligations: jury duty.

And as much as Chicago tried to play it cool, people here were entranced by the sight of a former president reporting to Room 1700 of a county courthouse, plopping a red juror sticker on his jacket and earning the $17.20 daily stipend — almost enough to pay for parking.

“He was willing to go through everything everybody else had to go through,” said Timothy C. Evans, the chief judge of the Circuit Court of Cook County, who spent part of the morning meeting with Mr. Obama, something not everybody else who comes for jury duty goes through.

What exactly was the fixation with seeing Mr. Obama, in a bland, cramped waiting room? For some, it seemed, it was the curiosity of someone like him doing something mundane, just like everyone else. (What might be next? Mr. Obama takes the driver’s test? Mr. Obama mows the lawn?) For others, it was the possibility — however remote — that Mr. Obama might actually be picked to serve on a jury. (Would the other jurors feel compelled to make him the foreman? And what might a defendant think if he walked into a courtroom and saw Mr. Obama over in the jury box?)