Twice every year, a test called the The Chuunin Exams held. This is the exam you must pass if you are to become a Middle Ninja. It's a 3 part test, and held for lower ninjas from any village. If you wish to enter you must have completed a minimum of 8 missions, and given the "OK" from your instructor.

The Chuunin Exams hold participants from, not just one village, but any village which a ninja qualified to enter. They are held in different villages each time, and because of convenience purposes, usually end up with mostly ninjas from the village hosting the Chuunin Exams.

These Exams also happen to have another purpose. Because people come from across the globe to watch the final test of the exams, they'll get to see ninjas from your village fight. After taking this into consideration, next time they happen to need a job done, they'll be much more likely to go to the village with the good fighting ninjas for the job, than the village with the bad fighting ninjas.  Which means, these exams can be very good for business.

Below you'll find detailed information on each of the 3 parts of the Chuunin Exams. We will be basing this information entirely on what was revealed in the Chuunin Exam taken by Team 7 early on in the series. The reason for this being information on other Chuunin Exams has not yet been revealed.

Chuunin Exams Test 1 - The Written Exam:

This test consists of a 10 question paper, which participants are given 1 hour to complete. Each participant starts out with a total of 10 points, and for each question you get wrong you lose one of those 10 points. If you ever reach 0 points you and the rest of your team will instantly disqualified. While the exam takes place several Middle Ninjas watch over the participants. Their job is to look for anyone who is cheating, and kick out anyone who reaches a score of 0. When they see someone who is cheating they penalize them for 2 points.
The last questions of the test works slightly different. It is not written on the paper like the rest of the questions, and isn't even the same question from test to test. This is what the 10th question was for the Chuunin Exams Team 7 took at the beginning of the series. When the 45 minute mark hit the teacher asked the participants if they would like to continue and try to answer question 10. If they answer question 10 wrong they will never be allowed to take this test again and forever be a Lower Ninja. In addition, all of their teammates will be disqualified.

If you choose to not continue, you will be disqualified along with your teammates, but will be allowed to try again next year. After everyone makes their decision the teacher congratulates them on their choice. They had just answered question 10 and passed the first part of the Chuunin Exam without even knowing it. The secret behind questions 10, was that the question about taking the question was the question! In other words, do you want to try to answer questions 10, was question 10.
Fun Fact: When Naruto was taking the written test, he didn't write down one answer on his paper, but because he answered question 10 correctly it didn't matter, and he passed this part of the exam.

Chuunin Exams Test 2 - The Forest:

This part of the Chuunin Exams takes place in Practice Area #44.  Also called the "Forest of Death", because of it's poisonous plant life and vicious animals. Participants are briefed on the exam 30 minutes before hand, and each cell if given one of two scrolls. The objective is to try to obtain the scroll you don't have, and reach a tower which is located in the middle of the forest. There are 44 locked gates which circle around the forest of death, in which the participants simultaneously use to enter the forest.
Each scroll is given out in secret so other teams won't know which teams have which scrolls, and which person is carrying the scroll in each team. You lose if anyone on your team is killed, tries to open the scroll, or doesn't make it to the tower with both scrolls. If a participant tries to open one of the scrolls, they will set off a spell inside the scroll causing anyone who looks at it to fall unconscious until the test finishes.

26 different teams made it to this part of the Chuunin Exams and entered the "Forest of the Death", however, only seven different teams successfully made it through forest and passed this portion of the Chuunin Exams. The participants who passed are: Hinata, Shino, Kiba, Gaara, Kankuro, Temari, Naruto, Sasuke, Sakura, and Kabuto.

Fun Fact: Gaara, Temari and Kankuro, arrived in the Tower, completing the test, in only 1 hour and 37 minutes. Beating the old record by 4 hours. On top of that Gaara didn't have one scratch on him.

Chuunin Exams Test 3 - The Tournament:

After seeing how many people passed the previous test, an announcement is made saying that too many teams have made it through and the number of participants needs to be cut in half before the Chuunin Exams can continue. So a preliminary round is held. It's at about this point that Kabuto decides to quit, saying that his body is to exhausted to continue.

The preliminaries are made up of one-on-one fights between all the remaining participants. The fights were chosen at random, and the winner of each fight would be guaranteed a spot in the Third Test. If a draw occurs neither participant would move on. All participants along with their instructors watch the fights. You lose if you give up, die, become unconscious, or are unable to continue for some other reason.

Here's the list of who fought who in the preliminary matches. The name of character who won is stated first, except in the case of a draw, where the character names are in Italics.

Preliminary Exam Winner: Round 01 - Uchiha Sasuke Round 02 - Aburame Shino Round 03 - Kankuro Round 04 - Haruno Sakura Round 05 - Temari Round 06 - Nara Shikamaru Round 07 - Uzumaki Naruto Round 08 - Hyuuga Neji Round 09 - Gaara Round 10 - Dosu Kinuta

Fought With: vs. Akado Yoroi vs. Zaku Abumi vs. Tsurugu Misumi vs. Yamanaka Ino vs. Tenten vs. Kin Tsuchi vs. Inuzuka Kiba vs. Hyuuga Hinata vs. Rock Lee vs. Akimichi Chouji

The 3rd and final test in the Chuunin Exams, is fairly similar to the preliminary matches. Like the preliminary matches the fights are made up of one-on-one battles between all the remaining participants. The fights are also chosen at random. However, unlike the preliminaries, if you win one match you go on to fight another until there's only 1 person left. Also unlike the preliminaries, you only increase your chances of becoming a Chuunin, not guarantee them. Another change is the enormous amount of people watching each fight. This audience of people even includes several Kages, and people from many villages.

Due to Sakura and Ino's match ending in a draw, as well as Gaara killing Dosu before the Tournament could take place, only eight people were left to fight in the 3rd test of the Chuunin Exams.
Unfortunately, we never get to see this tournament finish because of Orochimaru launching his attack againast Konoha in the middle of the Exams, but I'll give a brief explanation of who I feel would have won.

In round 1 (Naruto vs. Neji), Naruto wins, as shown in the series. Round 2 (Gaara vs. Sasuke), we never get to see complete in the Tournament, but we do see complete elsewhere. Sasuke loses to Gaara, and Naruto manages to save Sasuke and beat Gaara. This also means Naruto would have made it to the finals if the tournament wasn't interrupted. Round 3 (Kankura vs. Shino), In the series Kankura forfeits due to un-related reasons, but if he was to actually fight Shino it is un-clear to me who would win. However when we see Shikamaru beat Temari in Round 4, it's almost 100% clear that Shikamaru could beat either of them. This then leaves Naruto and Shikamaru in the finals. Who would win? Well, most likely Naruto. Shikamaru's only chance would be to quickly beat Naruto before Naruto got angry or used his best attacks which he always waits to use until later. But, like I said it's very unlikely that Shikamaru would wipe out Naruto fast enough. As I previously stated we can't know who would have really won the tournament and this is only my best guesses as to how it would play out.

Fun Fact: After all the incredible fights, and signs of great shinobi, only one of the participants became a Chuunin; Nara Shikamaru. However, in my opinion this is almost completely due to the fact that the tournament was brutally interrupted by Orochimaru, and the person who was in the position to assign these new Chuunin's was killed before he could make his decisions.