When I lived in California I seemed to get summoned for jury duty all the time. That's what it felt like, anyway (I think there was a set frequency, but I don't remember). The way they did it, though, was awesome. You show up and hang out from 8am until about noon. There was a ton of people that were there, and they called groups throughout the 4 hours. The expectation was that you stayed all day, but they usually had their juries more or less squared away by noon. If you weren't called, then you got to go home and your jury duty responsibility was considered fulfilled. I got called into a jury pool once. That took a couple more hours (we had to break for lunch). They started working through the jury pool and I was advancing up the line as they were dismissing jurors, but I ended up not getting selected.
California's method of jury duty is the only one I've experienced so far, but it sounds to me like it's the best (least intrusive).