Lawn bowls is a very old game that is played the world over. The object of the game is to get your bowls [which are biased so they'll roll in a curve] closer to the jack [which is a small white ball] than your opponents. Your team receives one point for each bowl closer to the jack than your opponent's closest bowl. It's quite simple, but can take years to master!
There are many variations of the game, you can have singles games, or teams of two to four players.
A typical team is three players. The team will include a lead, a vice skip, and a skip. The lead draws (rolls) the jack and then bowls first. The lead tries getting his bowls close to the jack. Each lead alternates bowls until they each bowl three times.
The vice skip has a more versatile role, depending on whether the lead has done the job well or not. S/he can continue to draw bowls close to the jack to add points or, if the lead has managed to draw the bowls to a closer distance to the jack than the opponent, the vice skip can try to bowl a short "blockers", to obstruct the opposition and protect the lead. The vice may also try to put in "back bowls", deliberately over bowling and playing his/her bowl past the jack, in case the skips bowls move the jack further down the green.
The skip has been watching every bowl and encouraging his team mates and suggesting shots. When they have finished, the skip will play all the types of shots described for the second player - except he/she will be better, having had more experience at playing them.
If the lead and vice skip are not finding the length or hitting the right line and have not got the "shot" [the bowl or bowls nearest the jack] the skip's job gets a bit tougher. He has to try to disrupt the "head" [the group of bowls around the jack]. He can do this by bowling his bowl on a tighter line and heavier, to differing degrees of weight. A full blooded drive, where the arm swings all the way back and the bowl is hurled down the middle of the green is known as a "firing" shot. Sometimes there is more skill involved if the bowl is play only slightly over weight, a shot designed to gently push out the shot bowl and leave your bowl in it's place, this is called a "running" bowl, and is harder to do. If your opponents have put in back bowls you may be forced to play running bowls.