I sat on two juries when I did jury service. I first case only lasted about an hour before the judge threw it out after the plaintiff was proven to be lieing ( the camera never lies ), the second case the defendant was found guilty and I was happy with the outcome. On the whole though it was pretty boring, lots of sitting around waiting to see if you are chosen or not to sit on a jury.
I got introduced (Not literally) to the Jeremy Kyle Show... Daytime TV still has a lot to answer for. At the time, a few people had the Nintendo DS game console and were playing the Dr. Kawashima brain training game.
The second week of mine fell on Easter weekend (The Courts don't sit from Maundy Thursday) so I had a four-day weekend off from the job I had at the time. Pretty sweet.
A clerk puts ( I think ) about 20 names in a hat ( so to speak ) and picks out 12. My stint was two weeks, however if you get chosen for a murder or a fraud case then I would expect it to go on longer than two weeks.
The first time was a nasty case, took ten days and I was happy to find the guy guilty. He got 10 years after all his past offences were revealed and taken into account!
The second time was absolutely shambolic, turned up most days and did nothing, went home after a few hours each day, and was discharged after two weeks without hearing a single case.
Two weeks is the usual length of time. They would let you know if a case would go on longer - you'd have to ask your employer for more time off to stay on.
I doubt that anyone would be welcome if they were drunk, Arksided (Someone might prove me wrong...).