It really is fun. Part of what’s fun is that it’s a fascinating exercise in storytelling. You watch a lawyer build his/her case and reveal things knowing full well that you are only getting a small part of the story and that even when both sides have finished you will only have an approximation of what happened, one that’s constrained by what’s can be admitted under the rules of evidence. It’s also fun because I have power to decide an issue that will have no impact on me whatsoever. So far I am impressed by the professionalism of everyone involved: the other jurors, the judge and the lawyers. Watching a court case really is good clean fun.
The hardest part for me is restraining my reportorial instincts. There are clearly a lot of interesting stories abutting the main one we’re hearing and I would love to track them down and get more information. Also I would love to research the background all on my own, but I don’t get to. Unlike being a reporter where you get to decide what the story is or isn’t, being a juror means having the story or stories told to you. While I’m trained to be an observer, I am also trained to be a fact ferret and this time the ferret has to stay home.
Collateral Damage 
I’m not sure, but I suspect that once the trial is concluded, there would be no legal or ethical barrier to honoring your reportorial instincts. Of course, if your investigation suggests the case was wrongly decided, that could really piss you off.