Hello, I'm just testing out this build on Shaco, which will be focusing on his Decieve to deal burst damage.

The key point is to get crit runes and build an infinity edge then trinity force, which will allow Shaco to deal amazing damage with his Decieve.

This build is meant to be a fun build not a superduper carry build that always works, so please don't get too serious...

Pros

Amazing burst damage.
Can out 1v1 anyone, including Trynd.
Fast backdoors
Dat Decieve feels sooooooooo good

Cons

Squishy
Fails if you fail in lane
Weak early game
Fails if your team fails

These runes are why I made a seperate build.
Runes by themselves grant 25% more crit damage, which is massive when you stack lots of damage.
On masteries, obviously pick up Lethality and Executioner.

You can go 9 utilities instead of Defense to grant yourself additional movement speed as well as longer buff duration, but I tend to play very agressively early, so I take +30 health masteries.

Your core build is Infinity Edge and you won't be dealing much burst without it.
Just keep farming or ganking until you gain 1650 gold.
DON'T buy that longsword or phage... they will slow down your build and destroy you. Remember, if you're trying to build a Critco, you MUST get infinity edge before doing anything. However, getting Zeal is a good idea cuz it will grant you survivability with its movement speed and increase your jungling speed.
Taking Brutalizer early game can be of advantage, but it won't be helpful late game since you won't be building Yomuu's Ghostblade. Brutalizer costs more than 1300 gold, just kill 20 more minions and take a BF Sword.

After IE, work into your Trinity Force. Trinity force woroks well with Shaco since he has innately high AD (114.7 at level 18 I believe). Then continue to stack AD with Blood Thirster. Of course, you can get 3 BT if you're doing extremely well, but I personally love the item Bashee's Veil, so I build it after my first BT.

Prioritize Hallu->Decieve->Two-Shiv-Poison->JitB. Nuff said.

I just set my Summoner Spells as jungler with smite, but please don't feel restricted to jungle when playing Shaco.
Lane Shaco works absolutely fine, but don't go bot unless you're duo queued with a friend. If you fail lane, Shaco will become absolutely worthless all game.

Go top and just harass the **** out of them with Decieve -> two shiv poison -> go into bush where you set up JitB. Shaco can beat top lane against almost any melee AD and mages except Mordekaiser and Irelia (Of course this depends on their skills and how their jungler plays).

If you plan to go in another lane, grab exhaust if you go top, grab flash if you go bot.
Flash on Shaco is good if you're always unaware of when to go in. If you constantly find yourself in the middle of the enemy team getting bursted down, by all means take it. If you can just beatifully clean-up the enemy team as an assassin is meant to, take ghost or exhaust.

Laning is always so much fun as Shaco, even after his box nerf.
keep a box in the bush that jungler will just have to find himself another guy to gank.
Spamming boxes unnecesarily is not a good idea since Shaco has low mana pool;
Most enemies will be smart enough to keep off bushes when laning against Shaco.
Also, minions sometimes proc your box aggro, so in that case if you have stacked 4 boxes in that bush it's a lot of waste of mana + unnecessary push.
Keep a box at the edge of the two bushes and Decieve in when they get dumb enough to proc your box.
Also don't forget how much damage your Backstab does;
it will secure kills in situations in which they may get away on 100 health.

Keep your eyes peeled for dragon or any battle going on at mid lane.
Don't feel hesitant to run to mid lane and help them; you have great mobility and ganking another lane will give lots of free kills early-mid game.

Also, don't forget that your crit deals more damage than smite!
You can easily steal their baron and dragon; of course you'll be left fend for yourself against a horde of enemy champions, but in most cases, it'll be worth it.

Another thing to note is your Hallucination.
I'm sure all of you guys know about his Hallu-dodge trick on cait ult and karth ult, so I won't be mentioning them here.
What I like to do is, if you see them camped up in a bush trying to ambush you guys, let your hallu walk in first and take the CC.

When towerdiving, use hallucination and let your clone walk slightly ahead of you to absorb the damage until you're close enough to the enemy to one shot them. Turret won't change aggro to you until you hit them, so make sure you're close enough to the enemy before throwing your two-shiv poison.

OK, so here's the most important part about Critco.
You must play him even more carefully than Master Yi, cuz Critco will be vulnerable for 9 seconds after his burst.

NEVER initiate, don't chase when more than 1 person is MIA on the map, and don't faill into dumb baits.
Wait for teamfights to start then come in from behind to 2 shot their ranged carry or mage.
Once you get IE and Trinity Force, you'll be dishing out insane damage when left alone, so just make sure their CC have been all wasted on your teank before going in.

Set up boxes near dragon, Baron, and other key points whenever possible, and try to plant a box on their escape route before ganking.

Don't go kill-hungry, stay low the higher killing spree you have.
Those people WILL focus you first out of the 5 champions on your team.
This means you can work as great bait; just let them chase you and decieve out as your team comes in.

OK, so here are some calculations on Critco, but I am uncertain whether they are right.
I'd be very grateful if someone explained how the calculations work on LoL.

Anyways this should be roughly correct;

Decieve damage: 2.2* 425
Critical Multiplier: 85%
Damage Multiplier: 6 (Executioner) + 1.5 (Havoc) + 20 (Backstab)%
Additional damage: 173 from Trinity Force

This Calculates around 1800 damage per Decieve.
A follow up Two-Shiv Poison and a free auto attack will grant over 2k damage easily.
In most cases, Decieve in, crit, Drop your JitB and Halluciante and run as your hallucination stalls time.
Remember how much damage your Decieve does and use it to kill those stupid enough to chase you by themselves.

I calculated Shaco's Decieve damage as the MINIMUM damage he could deal.
If his crit multiplier got multiplied and not added, then his decieve would deal 2k + damage by itself.

I made this build out of whim, so please don't be mad at me for it's abhorrent quality.
All I wished to do was just introduce you to a interesting build as Shaco which can work wonders when pulled off right.http://edge2.mobafire.com/images/insert-chapter.png