The best athletes in the world have long competed for their countries in the Summer Olympics—even if some of their respective sports were rather bizarre.

While some fans will spend their time watching basketball, swimming and soccer competitions at the 2012 games in London, a few others may remember the good 'old days of Finnish baseball, glima and korfball.

Korf...what? 

There have been plenty of wacky sports that have made appearances in the Olympics. Some still exist today, while others have been discontinued. Other sports were demonstrated in their respective years, which means the International Olympic Committee allowed a trial competition before accepting or rejecting the sport for future competition. 

Not surprisingly, the sports on this list were rejected.

Here are the 10 craziest Summer Olympic sports that have been discontinued or rejected after demonstration.

10. Roller Hockey

Year demonstrated: 1992, Barcelona

Ice hockey's close cousin made an appearance in the '92 Summer Games because it was one of the most popular sports in the Barcelona area at the time. Twelve nations participated in the competition, and Argentina captured the gold medal, Spain won the silver and Italy earned the bronze.

The roller hockey that had its shot at the Olympics is not the popular inline skating game that is widely played in the United States. This sport is played on quad skates, with four players on each team and a goalie. Instead of using a goalie stick and a glove, such as in ice hockey, a roller hockey netminder uses a flat batting glove that allows for plenty more rebounds.

9. Ballooning

Year demonstrated: 1900, Paris 

In the second-ever modern Olympic games, hot air ballooning was considered an Olympic sport. Not surprisingly, it was rejected for future competition after its demonstration year in France. 

Thank goodness.

Luckily, Olympic fans don't have to subject themselves to watching competitors flying hot air balloons. The competition consisted of participants having to fly their balloons as close as possible to a target, and then drop a weighted marker as close as possible it. There are no records of which nations competed in the 1900 games.

8. Basque Pelota

Year of Olympic competition: 1900, Paris

Years of demonstration: 1924 (Paris), 1968 (Mexico City), 1992 (Barcelona)

Basque pelota is a game that is a combination of racquetball and tennis. There are two teams with two players each, and there is usually a two-walled court. Some variations of the game include one wall, but the majority of versions use two walls. A team scores when the ball bounces off the wall and the opposing team fails to hit the ball before it bounces more than once. The game could also be played in a one-on-one format.

On the wall, there is a low line and a high line, and the teams must hit the ball between those two lines. Failure to hit the ball into this area results in a point for the other team. Different variations of a racquet, called a paleta, are used in different versions of the game. In one version of the sport, players use their hands instead of racquets. Ouch!

7. Water Motorsports

Year discontinued: 1908, London

Water motorsports was the term used back in the day, but today, the sport is most commonly referred to as offshore power boat racing. While the most high-tech machines fly around on the water in today's races, 1908 was the only year a motorized sport officially became an Olympic competition—and as you can imagine, the boats were still a work in progress.

There were three water motorsport races featured in the 1908 Olympics. All three called for the boats to circle an eight nautical mile course five times. Only two nations, Great Britain and France, competed in the three races. Great Britain won two out of the three races. After 1908, the International Olympic Committee decided that the Olympics were not intended for motorized sports.

6. Glima

Year discontinued: 1912, Stockholm

Glima is considered the "Icelandic sport of national folk wrestling." It differs from well-known wrestling in a few ways. The most obvious difference is that both competitors must always stand straight up, and they must circle clockwise around each other. The goal for each player is to get his opponent's body, anywhere between the elbow and the knee, to touch the ground.

The sport was demonstrated in the 1912 Olympics, but the International Olympic Committee rejected its proposal for future competition. Still, the sport is extremely popular in Iceland, and there has been an annual world championship competition since 1906.

5. Korfball

Years demonstrated: 1920, Antwerp; 1928, Amsterdam

Korfball is similar to basketball, with two teams of four players competing against each other. On each zone of the court, there is an 11.5-foot post with a basket on top. In each zone, the post is placed two-thirds of the way from the center line to the baseline. The sport is a mixed-gender competition, consisting of two women and two men on each team.

Like in basketball, the goal of each team is to score the ball, similar to a soccer ball in size, in its opponent's basket. There are two defenders and two attackers; the attackers could only stay in their opponent's zone, and the defenders must stay in their own zone and protect their hoop.

Players advance the ball by passing; running or dribbling with the ball is not allowed. There has been a world championship competition every four years since 1978, and the next world championship will be in Belgium in 2015.

4. Finnish Baseball

Year demonstrated: 1952, Helsinki

Finnish baseball, also known as pesäpallo, is eerily similar to American baseball. The sport made its lone Olympic appearance in its home country as a demonstration event before being rejected by the International Olympic Committee.

Like baseball, the Finnish version has a batting team with a goal of scoring runs, and a fielding team with the objective of getting three outs. Instead of a pitcher throwing towards the batter, however, a ball is tossed up high in the air vertically, and the batter has more control over where he places the ball. The game is played with two periods of four innings each. If each team wins one period, there is a final "super inning" to decide the match.

The batter has to reach three bases before scoring, similar to rounding the bags in baseball. However, the base paths are much different in this game.

3. La Canne

Year demonstrated: 1924, Chamonix

La canne, also known as Canne de combat, is a French martial art where participants use a cane as a weapon. Who wouldn't want to watch two competitors beat each other up with a large stick?

A bout takes place in a ring, and each player has a cane in one of his hands, but each is allowed to switch hands during the match. Horizontal and downwards thrusts and stabbing motions with the cane are used to attack opponent. Points are awarded for strikes to the opponent's head, torso or calves. 

Players wear a protective suit and fencing helmet to protect against the cane. However, both players cannot attack each other simultaneously. If one player makes a movement to attack, the other player must avoid the attack by dodging it or blocking it in a parry motion before countering with his own attack.

2. Australian Rules Football

Year demonstrated: 1956, Melbourne

No, Australian rules football is not the same as rugby. It is an awesome combination of American football and soccer with a splash of basketball, and you better have some stones if you want to play this game.

Australian rules football made its only Olympic appearance as a demonstration sport in its home country.

The game consists of two teams on an elliptical-shaped field, with 18 players on each squad on the field at once. The goal is to score points by kicking the ball through the opponent's posts, which is similar to a goal in soccer without the net.

Players can advance the ball by kicking it or running with it. Players running with the ball must bounce the ball or touch it to the ground every 15 meters. A fist-punching motion could be used to pass the ball.

The defensive team can stop the opposing team by tackling them or physically knocking the ball loose. The ball could be sent through the posts at any height, and it is worth six points. Two smaller posts are located on the outside of the large posts, and a kick through the area between one of the large posts and one of the small posts is called a behind, and it is worth one point.

1. Tug of War

Year discontinued: 1920, Antwerp

The same team game of strength that is played at picnics and barbecues across the United States was an Olympic sport from 1900 to 1920. Great Britain and the U.S. accumulated the most medals in the event during its time at the Olympics with totals of five and three for each country, respectively.

The rules of tug of war are simple. Two teams consisting of eight players each grab hold of a large rope. The large rope has a marking in the middle, and two marks four meters from the center mark on either side of the rope. Each team's goal is to pull the rope so that the mark on the opposing team's side crosses the center line, the starting point of the center mark on the rope.

Tug of war is still a popular sport today. It is included in the International World Games, and the Tug of War International Federation organizes a world championship for the sport every two years.