Golf's greatest team competition starts Friday morning, as the 39th Ryder Cup matches tee off at Medinah Country Club in suburban Chicago. The Ryder Cup is contested every two years between two teams of twelve professionals, one team from the United States and the other from Europe.

What had been a little-watched one-sided contest between the United States and Great Britain changed its format in 1979 to allow non-English Europeans like Seve Ballesteros and Jose Maria Olazabal to compete. The change leveled the playing field and turned the event into an Olympics-style patriotic battle. The Europeans dominated the 1980s, increasing tensions between the two teams -- particularly between Ballesteros and American star Paul Azinger -- culminating in the 1991 "War on the Shore" at Kiawah Island, which the Americans won. At the last Ryder Cup, European star Graeme McDowell rolled in a 20-foot putt to defeat Hunter Mahan 3&1 and give the Europeans the Cup.

The format of the Ryder Cup is unlike any other tournament. The event consists of 28 matches over three days, with each match worth a point. All matches are scored using match-play rules, and each match is in one of three formats:

• Foursomes: In foursomes, the players alternate their shots until the hole is completed. The team members also alternate tee shots.
• Fourball: In fourball, each player plays his own ball from tee to cup, with the lowest score for each team counting.
• Singles: Traditional one-on-one match-play format.

Friday begins with four foursomes matches in the morning and four fourball matches in the afternoon. The order flips on Saturday, so that each day holds a maximum of eight points. There is no requirement that all 12 team members participate in the Friday/Saturday matches. On Sunday, the teams square off in 12 individual matches. Each captain places his team in a playing order, and the players are paired according to that order. The team that wins the most points at the end of the day Sunday wins the Ryder Cup. In the event of a tie, the defending champion retains the Cup.

Ryder Cup coverage begins on Friday morning at 7:00 p.m. CT on ESPN and ESPN3, with the broadcast moving to NBC Saturday and Sunday.