Final Fantasy X/Overdrives

Summary

 * Tidus uses a bar to determine damage. Stop his overdrive in the middle by pressing psx: X before the time runs out to get max results.
 * Yuna uses a Grand Summon Overdrive. This allows one of her Aeons a full overdrive bar when Grand Summoned. It is stackable (meaning if you Grand Summon an Aeon who already has a full bar, you'll be able to use their overdrive abilities twice).
 * Lulu rotate the right analog psx: Neutral Rstick to determine the amount of times Lulu casts a magic spell of your choice.
 * Auron uses a combination of buttons to damage all enemies with a massive attack. More can be learned by finding Jecht Spheres.
 * Kimahri absorbs the talents of many of his enemies to do damage. He must use Lancet on certain enemies before he is able to learn.
 * Wakka uses different slot machines to damage enemies depending on your luck. Use X to stop each column.
 * Rikku mixes different items in your inventory to get different results.

Tidus
To get Tidus's overdrives to inflict maximum damage, you must successfully stop a pointer scrolling along a bar in the middle section as quickly as possible. If you fail to do this in the time allotted for the attack, Tidus will hit for minimal damage if at all.

Yuna
Yuna's overdrive is Grand Summon. It will summon any available Aeon, but supply them with a full overdrive bar. After using this overdrive the Aeon's overdrive bar goes back to what it was before it was summoned, meaning that 2 overdrives in a row is possible if the Aeon has full overdrive and is then grand summoned.

Lulu
Lulu's overdrive is called Fury, and when activated you must choose one black magic ability that will be cast many times. Any black magic spell can be used, and the process does not require any MP. You then have 4 seconds to rotate psx: Neutral Rstick as many times as possible, with the amount of spells that will be cast building up as you rotate it. More powerful spells require more rotations to add an extra spell to the counter, and a higher magic stat reduces the number of rotations required to add an extra spell to the counter. The spells are cast randomly against the enemies at half normal casting strength. An enemy can be hit multiple times (although it will not be hit any more if it dies, so your spells aren't wasted), and the total damage of all the spells that hit it (rather than each spell individually) determines an overkill.

Note: Since Bio doesn't inflict damage, Bio Fury uses spells that have roughly a half as likely chance of inflicting poison on the targets (the actual chance is then determined by status effect resistances, for example a monster with no resistance to poison will succumb to a spell from Bio Fury half the time, and one with a 50% resistance to it will succumb 25% of the time). Demi Fury spells hit for 1/8 of the target's health rather than 1/4, and some monsters that are affected by Demi (bosses in particular are often immune to gravity) may be immune to Demi Fury. Death Fury works in a similar way to Bio Fury.

Auron
Auron's overdrives do the most damage when the button sequence that appears on the screen is inputted before the allotted time is up.

Dragon Fang

 * has these button commands — psx: Down Dpad, psx: Left Dpad, psx: Up Dpad, psx: Right Dpad, psx: L1, psx: R1, psx: C, psx: X
 * hits all enemies for slightly more than an ordinary attack
 * only hits one enemy if the button sequence is not completed
 * you always have this overdrive

Shooting Star

 * has these button commands — psx: T, psx: C, psx: S, psx: X, psx: Left Dpad, psx: Right Dpad, psx: X
 * hits one enemy for high damage, may Eject them
 * no Eject effect if button sequence is not completed
 * collect 1 sphere to obtain

Banishing Blade

 * has these button commands — psx: Up Dpad, psx: L1, psx: Down Dpad, psx: R1, psx: Right Dpad, psx: Left Dpad, psx: T
 * hits one enemy for high damage, inflicts all four breaks (100% chance) if enemy not immune
 * only inflicts one random break if button sequence is not completed
 * collect 3 spheres to obtain

Tornado

 * has these button commands — psx: X, psx: Right Dpad, psx: R1, psx: Left Dpad, psx: L1, psx: T
 * hits all enemies for high damage twice
 * only hits once if button sequence is not completed
 * collect all 10 spheres to obtain

Collecting the Spheres
The spheres only appear after you beat the boss in Macalania Woods, immediately after which you will gain your first sphere (and Auron's second overdrive). Therefore spheres listed in locations met early in the game can only be obtained later on. The spheres have a similar appearance to Al Bhed primers, and are picked up in the same way (by pressing psx: X). When you collect a sphere you will watch a short scene from Lord Braska's pilgrimage 10 years ago, where you will find out more about Auron, Jecht and Braska. After the scene, the sphere will disappear and if you have enough one of Auron's overdrives will be unlocked.

Wakka
Wakka's overdrives are based on sets of reels which you need to stop in various combinations to achieve maximum effect, although the Aurochs Reels are not necessarily bound by this.

Element Reels

 * available from the start of the game
 * hits either one or all enemies with an attack combined with the element on the reels (two or less of one element hits one enemy, all three of the same element hits all enemies)

Attack Reels

 * available as 1st prize from the first blitzball tournament you can enter (ignoring the storyline-based one in Luca)
 * randomly hits all enemies with physical attacks, an amount which is determined by the values on the reels (maximum is 12 hits)

Status Reels

 * available as 1st prize from blitzball league (appears randomly)
 * attacks cause status changes(3 skulls = Silence, Poison, Darkness, and Sleep; 3 hourglasses = Petrification; 3 pointers = Full Break)

Aurochs Reels

 * available as 1st prize from blitzball tournament (appears randomly)
 * combination of all kinds of Reels plus a new symbol — Aurochs. 3 Aurochs cause a special attack.