The only time I've played was on a weekday evening, with teams of 11. Each team has an innings of 22 overs, with each player bowling 2 overs. From memory it may have taken 2-3 hours for the whole game. We played with a proper cricket ball and pads, which was ok but, if you're a bit of a beginner, ideally it would be nice to get your confidence going with a less scary ball at first.
It was pretty good fun - despite the fact that I'm sh*t.
Its a nice way to spend a summers evening for sure.