You have to feel bad for baseball and softball rookies who reached the major leagues last season. Beijing was the swan song for these two sports as they were pulled off the Olympic calendar for London. They will be replaced by golf and rugby sevens, that will come in for Rio 2016.
To be eligible for the Olympic Games, a sport must be widely practiced around the world overseen by an international federation and cannot involve any motorized element.
As can be imagined, many events meet those criteria and are still not on the calendar. Let's look at some of the contenders:
Karate: With fencing, judo, taekwondo, boxing and wrestling already in the Games, karate has been crowded out by other martial arts. Its supporters are clamoring that it is arguably better known worldwide than taekwondo but there is another political problem. There is no single recognized style of karate. It is split up among different schools and the IOC would have a tough time choosing one.
Chess: Perhaps more ridiculed than any other applicant, the World Chess Federation has been waging a very long battle to prove it should be part of the Olympic Games. Following IOC guidelines, they even adopted drug testing for competitors, which was more farcical than it was useful. Advocates also say that chess would be a welcome intellectual addition. I know I might make my chess champion grandfather roll in his grave but I am not convinced. Chess boxing, on the other hand, there is a sport I can get behind.
Sumo: If there is a God, sumo will be an Olympic sport one day. Beyond being a shot in the arm for a sport struggling to survive, the sight of sumo wrestlers in the athletes' parade would be entrancing. The Olympic Village sex antics might take on a whole new dimension.
Dancesport: In other words, competitive ballroom dancing. Since being officially recognized by the IOC in 1997, the World DanceSport Federation has been the geeky kid trying to get a seat at the cool table. Its website is very proud of the progress it has made but it faces an almost insurmountable problem. Amid showcases on the track or in the pool, very few people are likely to watch ballroom dancing.
I realize this argument can be made for more obscure Olympic events, but anyone not watching Vanuatu vs. Moldova in the water polo prelims is just missing out.