I served as a mock juror on a mock trial one time, and it was a very interesting experience. I got the job by signing up at a professional survey company in a local shopping mall. We were told to report to a room in their office suite the next morning. They only asked us if we had any connection to local media outlets. The client didn't want details of the "lawsuit" leaked to the general public.
We were split into two juries, but we all heard the same testimony at the same time. The case involved a woman who was severely burned by gasoline she brought into her new home to remove some spilled paint. The fumes from that gasoline made contact with a live pilot light on a gas water heater and triggered the fire. She was suing the manufacturers of the water heater for not keeping the flame 18 inches above the ground.
There were real attorneys arguing for both sides, and the judge made sure we only heard what would have been legally admissible in a real court. Some of the witnesses seemed more credible than others, but I couldn't tell if they were actors reading from a script or real experts testifying the way they would in a real court. It was a very convincing performance, either way.
I was elected foreman of one jury, and we spent a few hours deliberating the facts of the case. It became apparent that most of us sided with the defense, since the woman brought the gasoline inside her house and should have realized what a bad idea it was. She got burned by an act of neglect, not a design flaw with the water heater. But we still had two hold-outs who thought the company owed her millions of dollars in damages. The day ended with a finding in favor of the defendant, but an imaginary award of 3 million dollars for the plaintiff if she had a better case.