Chocobo Trainer is a mini-game from Final Fantasy X. Located in the Calm Lands is a chocobo trainer, and he will let you train on the chocobos. The chocobo trainer, if you come into the calm lands from the Macalania Forest entrance, will be in the North-west area. If you come via the Airship he will be directly south of the shops.
Just talk to him to initiate one of the four training exercises. You must beat the record before the next one is unlocked.
The four exercises that you will be able to do are:
 Wobbly Chocobo
The aim of this exercise is to guide the chocobo to the finish line, however you must beware, the chocobo is somewhat unable to walk in a straight line. Beat the time of 12.8 seconds to unlock the next exercise. You can also travel by chocobo in the calm lands by talking to the trainer at anytime after completing this training exercise.
 Dodger Chocobo
The chocobo now goes in the direction that you tell it to, however you must now dodge blitzball that come flying out of nowhere which are aimed towards you. Getting hit by the blitzball will result in a penalty of 3 seconds. Beat the record to unlock the next exercise.
 Hyper Dodger Chocobo
This is the same as Dodger Chocobo exercise, however this time you will be bombarded with Blitzballs and birds, both of which you must avoid and get to the finish line and to top it all off you must beat his record. Watch out as the blitzball hits the ground it will split into pieces which may hit you as they fly off to the side.
 Catcher Chocobo
This is more of a race than a training exercise, and you will need to do it to get Tidus's Sigil and Celestial Weapon.
What you must do is race against the trainer in an attempt to reach the finish line. The catch is that there are birds that come flying into you (generally 3 birds will fly into you, and then another 3 will fly into the trainer then 3 birds will fly back at you and so on) which immobilise you for 1.5 seconds. There are also balloons which you must get, however the trainer is also able to get them so you must try to stay ahead. You cant control the speed of the chocobo just the direction (left and right). Now for the biggest catch, even if you beat the trainer in reaching the finishing line, to actually win you have to take into account how many Balloons you have collected and how many birds you were hit by. Each bird that you hit will increase your overall time, where as each balloon that you collect will deduct the total time by 3 seconds. You will need a time of better than 0.00 seconds to get Tidus's Sigil.