Put quite simply, this is a guide to the new PvP-centric zone in Wrath of the Lich King that goes by the name of Lake Wintergrasp. This is the first guide I've written in a looooong time, and the reason I'm writing it is because Wintergrasp (hereafter referred to as WG) is just ten kinds of awesome. It really is a fun zone, and the dynamics of play between assaulting the fortress and defending it are very engaging.
Lake Wintergrasp Background
First off, what is Lake Wintergrasp, and why should you play it? As noted above, it's a PvP-focused world zone in the WotLK expansion pack. It's a medium-sized zone that is the focal point for a vicious battle between the Horde and Alliance for control over the fortress of Wintergrasp. Controlling WG gives every member of your faction in Northrend a buff that increases all experience gains by 5% and allows bosses in every instance (yes, every instance) to drop what are called Stone Keeper's shards. If you've ever done the Auchindoun instances with the Terrokar buff on, the Keeper's shards are similar to the Spirit shards you would acquire there, only the selection items that can be bought with Keeper's shards is much greater.
List of items you can buy with Stone Keeper's shards
If that wern't incentive enough, a single battle of WG can easily give up to 5000 (five thousand) honor, even for a loss. This is in addition to any honor gained from directly killing enemy players. Having control of the Wintergrasp Fortress also gives your faction a "PvP hub" of sorts, as portals to each of the battlegrounds exist inside the fort, as well as a portal to the Violet Citadel in Dalaran. In other words, doing Wintergrasp is not only very fun, but also very profitable in a number of different ways.
The Parts of Wintergrasp
Wintergrasp is broken up roughly into three parts; the Fortress, the northern Workshops, and the southern Workshops and towers. When WG is "dormant" (that is to say, the 2.5 hour period of time between battles) the northern workshops and fort are occupied by the faction that most recently won Wintergrasp, while the southern workshops and towers are listed as neutral (gray) and are guarded by NPC's of the opposing faction. All workshops, including those within the fort itself, are disabled while WG is dormant. This means the only time you can use siege weaponry in WG is during an actual battle.
As you can see in the above screenshot, the Alliance has control of the Fortress and northern Workshops, while the southern Workshops are listed as neutral. The southern workshops still have Horde NPC's guarding them, as do the three southern towers. There are five graveyards total in Lake WG, one for each of the northern and southern Workshops, and one at the back (north) of the Fortress that is used solely by the defending force.
During a battle period, control of the map changes slightly. The two northern Workshops fall under the control of the attacking faction, and are now considered objectives that can be captured by either team. This means the attacking force starts out with four (4) workshops at the beginning of a WG battle, while the defending force starts out with two (2), namely the two inside the fort. This is important, as the number of workshops you control influences the number of siege vehicles that you can employ on the battlefield at one time. Each workshop counts as four vehicles, meaning an attacking force starts out with a potential for sixteen (16) vehicles while the defenders start with half that, eight (8).
Of the six workshops, only the northern ones can be captured, Eye of the Storm tower-style (as far as I'm aware). My understanding is that while the southern and fort-based workshops cannot be captured, they can be destroyed (the northern ones are immune to damage of any kind). Under certain circumstances, this can force some interesting engagements at the northern workshops, as the battle becomes about securing resources (siege engines) more than actual fortress assault/defense. However, the time limit of WG battles generally keeps this kind of conflict short, with the defending side inevitably winning.
Of the graveyards, the "natural" Alliance and Horde graveyards while on offense are, respectively, the northeast one and the northwest one. However, just because you're sent to a certain graveyard doesn't mean you have to stay there. Blizzard has implemented a few key mechanics that help fight against being outnumbered, being camped, or being forced into a bottleneck or surrounded.
Tenacity, Spiritual Immunity, and Graveyard Porting
The first, and most important mechanic, is known as the tenacity buff. One of the common complaints about Wintergrasp during beta was the possibility of heavily unbalanced numbers greatly favoring one faction or the other. In essence, an outnumbered faction would stand no chance just on the basis of sheer numbers, even if the outnumbered faction somehow had an advantage in siege weaponry. Tenacity is the answer to being outnumbered.
Whenever there is an inequal amount of players on both factions in Wintergrasp, the side that has the lower number of players receives what's called the Tenacity buff. This buff increases your health, your damage dealt, your healing received, and the honor you gain from kills. Tenacity buffs also stack based on how great the inequality is, so the more you are outnumbered, the stronger you get. The most I've personally had was a stack of twenty-seven (27) tenacity buffs. At level 76, this gave me over 60k health and something like +320% damage to all my attacks, as well as over 100% extra honor gained per kill. In short, I was a player-controlled raid boss. I felled a goodly number of 80's before the enemy finally wised up and came at me in overwhelming numbers (it took about eight 80's to bring me down).
As the number of players on either faction begins to even out, the Tenacity buff begins to lose stacks, until when things are roughly equal (no more than one or two players difference) it is removed entirely. Tenacity affects everything you do, from the damage you deal with spells or auto-attacks, to the flame breath and health of your Catapult, to the destructive power of the anti-vehicle RP-GG (Rocket Propelled Goblin Grenade).
The second mechanic, the anti-camping mechanic, is called Spiritual Immunity. This one is pretty self-explanatory. Basically, whenever you are within a certain distance of a graveyard, you are immune to everything. You cannot die. At all. This mechanic is designed specifically to combat people who like to graveyard camp. Each one of the graveyard spawn points are far enough removed from any objective of importance that if a person or group of people were to attempt camping, then it's clear that they're just being bastards. As such, Spiritual Immunity exists to give the camped side not just a fighting chance, but a way to completely and utterly destroy the campers with impunity (and gain some nice honor in the process).
Thirdly, this mechanic is one that I've found to be the most innovative. Basically, it combines an anti-camping mechanic with a means to break any kind of bottleneck or chokehold. This mechanic is Graveyard Porting.
Put simply, if you are attacking and are dead and you don't like the graveyard that you have been sent too (say, it's near a workshop controlled by enemy forces who outnumber you) then you can right-click on the spiritual healer there and choose another graveyard, any graveyard (save the Fortress one) and choose to be teleported there, where you will rez. This allows blockades to be easily broken (or flat out ignored) and ensures the attacking side always has access to a Workshop.
Finally, there is one other unique WG mechanic that doesn't fall into any kind of category, the Rank mechanic. Basically, as you kill NPC's and players of the opposing faction, you gain rank. As you can gain higher rank you gain access to more advanced siege weapons. The only two ranks implemented at the moment are Corporal and First Lieutenant (for Alliance, I'm unsure as to what Horde have for ranks). Corporal rank allows you to access the Catapult, a fast anti-personnel and anti-static defense siege weapon. The First Lieutenant rank allows you to access the Demolisher, a medium siege weapon with decent anti-personnel capability, a two (2) passenger+one (1) driver capacity and strong siege power, and the Siege Tank, a heavily armored (and slow as heck) tank with enough room to hold a driver, two (2) passengers and one (1) gunner. Each of these vehicles has their strengths and weaknesses, and each is uniquely suited to handling various situations.