[skp]

Those are good Cliff's notes.

[ QUOTE ]
There are some fielding restrictions at the start of a ODI, but I'm not really well versed in those. There are also no balls and wides, I forget exactly what these mean to scoring. They don't count towards the six pitches/over

[/ QUOTE ]

Wides and no-balls add 1 run to the batting side's score.

Fielding restrictions:

The first Ten overs are called powerplay 1. At that time, only 2 fielders are allowed outside a 30 yard circle radius from where the batsmen are standing. The other 7 fielders including obviously the bowler and wicketkeeper are inside the circle. Further, of the other 5 fielders, 2 of them must be within 15 yards of the batsmen in what are known as catching positions. All of this is designed to encourage an explosive start to the innings where guys can get 4's and 6' more easily.

Powerplay 1 is mandatory in the first 10 overs.

Then, at some point in the match at the fieding team's choice, the fielding side must use Powerplay 2 (a 5 over block) and powerplay 3 (another 5 over block). During these powerplays, there still can only be two guys outside the 30 yard circle but there is no need to station 2 guys in catching positions.

The fielding side almost always opts to take powerplays 2 and 3 between overs 10 and 20. They do this to avoid having to take the powerplays later on when the real push for big hits begins.

Once the Powerplays are over, the fielding side is allowed a maximum of 5 players oustide the 30 yard circle.

Generally, you will see the fastest scoring in the first 10 overs and the last 10 overs of a one day innings. The middle period of 30 overs will usually see batting teams poke the ball around into gaps in the field and take single runs. There are a lot more 4's in the first 10 overs and a lot of 4's and 6's in the last 10 overs assuming that the batting side has not lost too many wickets by then.

The bowling side is expected to deliver about 15 overs in an hour (called the "over rate"). So, a 50 over innings generally lasts 3.5 hours. They then have a 30 to 40 minute break followed by the other team batting for 3.5 hours.