Like any sport, lawn bowls has its own set of rules which are fairly lengthy.
The basic idea is to deliver (or roll) a bowl along a grass surface to get it as close as possible to a white ball (the jack). In a game, whoever's bowl is closest after all the bowls have been delivered wins the end (or mini game). It may appear simple, but the bowl has a "bias" which makes it curve and the grass changes deepending on the weather and the time of day.
However, for a description of what the game is about, click the button.
If you'd like to see how it's done, here's a short video which shows the basics of delivering a bowl. It was filmed in South Africa, but is equally relevant in the UK (although our greens are normally slower).
If you really want to see the full Rules of the game as they apply in England, you can find them here: