I'vd been called once. In this county, you can be called for grand jury duty, or you can be called (more commonly) as part of that week's jury pool. The pool is for all trial juries, both criminal and civil, on the docket for that week. Worst case, you sit on your butt for 5 days, and never even get enpanelled, because there aren't enouggh cases on the docket. Best case, they already know there aren't enough and you get released immediately.
I actually sat on a jury in (of all things) a divorce case. They settled a day and a half into it.
The reason you can't talk about the case until after it's over is that they don;t want ANY communication leaking back to the defendant, his lawyer, or the prosecutor. This is referred to as "ex parte" communication (if I remember right), and it can void the whole freaking trial, as it then becomes AUTOMATIC grounds for appeal.
All in all, it's no big deal. If I get called again, I'll go again.