Corki might be one of the worst champions to play but if you follow this item build you will get your kills in no time. (Have to have some experience with floating Manatee and some experience with a Gatlin Gun to play this Champion.) (Also... skip to the Pro's and Con's below to skip all this ****...)

Lore:

When Heimerdinger and his yordle colleagues migrated to Piltover, they embraced science as a way of life, and they immediately made several groundbreaking contributions to the techmaturgical community. What yordles lack in stature, they make up for with industriousness. Corki, the Daring Bombardier, gained his title by test-piloting one of these contributions - the original design for the Reconnaissance Operations Front-Line Copter, an aerial assault vehicle which has become the backbone of the Bandle City Expeditionary Force (BCEF). Together with his squadron - the Screaming Yipsnakes - Corki soars over Valoran, surveying the landscape and conducting aerial acrobatics for the benefit of onlookers below.

Corki is the most renowned of the Screaming Yipsnakes for remaining cool under fire and exhibiting bravery to the point of madness. Before the League, he served several tours of duty, often volunteering for missions which would take him behind enemy lines, either gathering intelligence or delivering messages through hot zones. He thrived on danger, and enjoyed nothing more than a good dogfight in the morning. More than just an ace pilot, Corki also made several modifications to his copter, outfitting it with an arsenal of weapons which some speculate were more for show than functionality. When open hostilities ceased as part of the agreement surrounding the formation of the League, Corki was forced into a retirement which he felt ''cut the engines and clipped the wings''. He tried to make do with stunt flying and canyon running, but it was never the same without the refreshing smell of gunpowder streaking through the air around him. When Heimerdinger joined the League of Legends, it was no surprise to see Corki follow soon after, eager to test his mettle against the best the world has to offer.

He is Corki - death from above!

Abilities:
Hextech Shrapnel Shells:
Corki's basic attacks deal 10% additional true damage to minions, monsters, and champions.

Phosphorus Bomb:
Deals 80 / 130 / 180 / 230 / 280 (+50% of ability power) damage to enemies in a target area. In addition, the blast reduces an enemy's chance to hit by 35% and reveals nearby stealthed units for 3 seconds

Valkyrie:
Corki surges to target location dealing 60 / 90 / 120 / 150 / 180 (+40% of ability power) damage per second to enemies in the fire left along his path.

Gatling Gun:
Corki's gatling gun fires at all targets in front of him for 3 / 3.5 / 4 / 4.5 / 5 seconds, dealing a quarter of his total damage and shredding 1 / 2 / 3 / 4 / 5 armor with each shot. The armor reduction persists as long as the enemy is under continuous fire.

Missile Barrage:
Corki fires a missile towards his targeted location that will collide with the first enemy it hits. Each missile deals 125 / 200 / 275 (+30% of ability power) area magic damage.

Corki stores one missile every 14 seconds up to 7 missiles at any given time. Every 4th missile will be a Big One.

Pro's & Con's

Pro's:
Excellent harras abilities.
Excellent escape ability.
Underestimated, so a lot of your opponents will play way more offensive then normal.
Ultimate that can be spammed with a large range
Alot of AOE damage abilities.
Can get first blood easy.

Con's:
High cooldown on escape ability.
When focussed can be easily killed.
Can no longer see invisiable units :(.

Summoner spells

In my oppinion this 2 are the best to take:
Exaust: is just a great spell, if someone run you can use it. and when you are fighting an opponent with heal, consider it to use in the middle of the fight, so they will only be health for half of the normal amount.

Ghost: An excellent escape ability for when valkiry is on Cooldown or to use right after you did valkiry. Also it's very good to chase enemies

Summoners spells you COULD get

Flash: For the same reasons as Ghost, but its just like Valk.

Teleport: Teleport is fun if you have wards all around the map.

this is a spell that can save your live against disablers.

Summoner spells to AVOID!
Clairvoyane: unless you are a person who likes to know where ganks are and what is happening then dont get this...

Clairty: You can get this it is completely on choice but they way you go Auto attacking is all you do.

Cleanse: This is a spell a tank or support should choose.

Smite: You won't jungle with corki, so there is no reason for taking smite. But hey if your into that do it.... ive done jungle Himer before...

Items...
For items I start off with a Doran's Blade because of the health, damage, and life-steal.

I get a second one for the same reason normally I have the second one in the first 2 minutes of the game because of the First Blood.

Then I get the boots.

After those i get Phantom Dancer because you will notice you will be crittinng alot more now
and you farm creeps alot easyer.

Then Infinity Edge.... what crit build would be without one of these.

Then another Phantom Dancer.(If your not OP by now and killing people easily your doing something wrong.)

After that you can sell one of the Doran's Blades and pick up one of your choice Blood Thirster or a Executioner's Calling.

Then sell the other Doran's Blade and get then another Blood Thirster.
(By this time you should have no problems killing people.)

When its all over if you went with a Executioner's Calling and Blood Thirster you will have 110% Crit and if you went with 2 Blood Thirsters you will have 95% crit.

I made this whole build up because of the Urfrider skin. I MEAN COME-ON HE THROWS A SPATULA AT SOMEONE IF HE CRITS!