Yet again, the idea is not new. Emrakul is a win card, certainly when getting it out at third turn.
So how I do it: best possible hand to start with (in case your opponent is not simply countering everything) has 2 lands (1 white / 1 green, where green is a must have while you might rely on drawing a white one later), 2 elves, 1 pattern, 1 worthy cause or scapegoat, and one lightning greaves...
- You play Forest / Temple Garden (-2) and cast an Elf
- then you play another Land, plains or high market would be nice. Forest is OK when you have a high market in your hand or trust in drawing a white mana card.
... Anyway, bring out another elf, and use the other 2 mana for the lightning gleaves.
- 3rd turn: buddy, respond or die! I play a land, cast pattern on one of my elves, using both their mana abilities, so that I either have a white mana left for Worthy Cause or Scapegoat left or I use the high market instead to sacrifice the elf with pattern.
- search for one of the Legends (the one that fits the situation best), give it a kiss and finish the game.
THE THINGS IS: As Emrakul was not "cast" from your hand, you do not get the second round (which you do not really need when lightning gleaves are there to equip him), so your opponent might have something to get rid of Emrakul in his round, before you can attack and destroy everything... opponents cannot target it directly with colored spells, but abilities can... so maybe you might want to consider bringing Progenitus or Iona onto the battlefield instead - depending on opponent's abilities.
In case you draw on of the Legends, use Dawnstrider to get it back to your library.
Vexing Shusher is sooo nice against counters. I love that little fella.
Order of the Stars are lovely... For each color... Of course, dont play them first round before you know color(s) your opponents plays. If it is an artifact deck, be careful...
I dropped Disenchant for more Oblivion Rings due to the fact that Planeswalker are annoying most of the time, and sometimes Swords to Plowshares just do not want to come. 3 converted mana cost instead of 2 for a disenchant seems reasonable to me here. Most of the badass enchantments and artifacts cost more than 3 to play, so it is OK... Saved my life to exile cards like Call to the Grave or Karn Liberated...
I read that cards like oblivion ring and journey to nowhere can exile Emrakul as they do not target directly, so no protection. Therefore, I needed to come up with some alternative and Iona + Progenitus can handle most situations.
In the end, no matter how to get Emrakul out early (elvish piper or polymorph also works fine), I love the reactions :)