The Ryder Cup is a unique (and dramatic!) three-day event that uses three different playing formats during the competition: foursomes, which is also called alternate shot, fourballs and singles. Below is an explanation of foursomes, according to the Ryder Cup’s official site:
In foursomes, each two-man team plays one ball per hole with the players taking turns until each hole is complete. Players alternate hitting tee shots, with one leading off on odd-numbered holes, and the other hitting first on even-numbered holes. The team with the low score on each hole wins that hole. If their scores are tied, the hole is halved.
One other note, players can still concede holes or strokes at any point along the way. More from the Ryder Cup site:
Unlike stroke play, players don’t have to complete each hole in match play. If a player concedes a stroke – almost always a putt – to his opponent, the opponent picks up his ball, takes the score he would have made on the next stroke and moves on to the next hole.
Foursomes is a fun format, and arguably the most challenging of the three styles used at the Ryder Cup. You need pairings with golf games that complement each other, personalities that click and — perhaps most importantly — you need players who keep the ball in play and give their partner a chance. There’s extra strategy involved (for example, do you want to line up a longer hitter to tee off on the par 5s? Is there a solid iron player who might be able to take three or even four of the par 3s?) and because of the inherent difficulty, pars often win holes in this format.
One final wrinkle: because players use only one ball per hole, they may have to adapt to their partner’s golf ball if they don’t already play the same brand.