Gnomeregan

Gnomeregan was the capital city of the gnome race until a trogg invasion led to its tragic downfall. The city is currently a mid-level instance. The few gnomes still left in the city fight desperately to keep the troggs at bay. Gnomeregan is a unique instance in that it possesses a friendly NPC section inside the dungeon itself, including vendors, guards, a repair station, some new quests and even a mailbox.

Gnomeregan is also unique in that it has a very technological (and somewhat comical) theme.

The instance is also particularly notable for the Hydrocane Rare Staff which drops from an early mini-boss, Viscous Fallout. The staff allows permanent water breathing, and as such is often still carried and used situationally even by very high level characters. The staff is thus situationally beneficial to all character classes that are capable of equipping staff weapons.

History
From WorldofWarcraft.com:


 * When the war against the Burning Legion ended, the Alliance discovered the reason for the Gnomes' sudden withdrawal. Apparently, an ancient, barbaric menace had risen from the bowels of the earth and invaded Gnomeregan. Knowing that their allies' priority was defeating the Burning Legion, the Gnomes decided to make their stand alone. Though they fought valiantly to save their beloved city, Gnomeregan was irrevocably lost.


 * Located in Dun Morogh, the technological wonder known as Gnomeregan has been the gnomes' capital city for generations. Recently, a hostile race of mutant troggs infested several regions of Dun Morogh - including the great gnome city. In a desperate attempt to destroy the invading troggs, High Tinker Mekkatorque ordered the emergency venting of the city's radioactive waste tanks. Several gnomes sought shelter from the airborne pollutants as they waited for the troggs to die or flee. Unfortunately, though the troggs became irradiated from the toxic assault - their siege continued, unabated. Those gnomes who were not killed by noxious seepage were forced to flee, seeking refuge in the nearby dwarven city of Ironforge. There, High Tinker Mekkatorque set out to enlist brave souls to help his people reclaim their beloved city. It is rumored that Mekkatorque's once-trusted advisor, Mekgineer Thermaplugg, betrayed his people by allowing the invasion to happen. Now, his sanity shattered, Thermaplugg remains in Gnomeregan - furthering his dark schemes and acting as the city's new techno-overlord.

Encounters

 * End Boss: Mekgineer Thermaplugg Level 28 Elite
 * Mini Bosses:
 * Viscous Fallout 28 elite
 * Grubbis 28 elite and Chomper 26 elite.
 * Electrocutioner 6000 28 elite
 * Crowd Pummeler 9-60 28 elite
 * Rare Spawns:
 * Dark Iron Ambassador

Loot
Loot updated for Patch 2.3.0.

Maps

 * Gnomeregan Map with quest notes.
 * A large map from videogamemaps.net.
 * Gnomeregan Map from Atlas.

Resources

 * allakhazam's guide to Gnomeregan

Dungeon Denizens

 * Alarm-O-Bots
 * Dark Iron dwarves
 * Gnomes
 * Gnomish mech
 * Leper gnomes
 * Mechanostriders
 * Oozes
 * Spider tanks
 * Troggs
 * Water elementals

Notes, Tips, & Additional Info

 * Also known as GR, Gnome, and Gnomer.
 * Pronounced Gnom-re-gan
 * In many threads littered about the WoW Official forums, Gnomeregan is widely regarded as the "Worst Instance Ever", often due to the difficulty of certain pulls, how easy it is to wipe, or simply hatred of the music or the gnomes themselves.
 * Grime encrusted objects can be washed in the Sparkle-o-matics for random junk, and sometimes green necklaces or rings. Since the area is filled with alliance-friendly npcs, Horde players will have to fight their way in.
 * Mobile Alert Systems will happen upon your party from time to time, destroy these ASAP or risk being attacked by a lot of enemies that drop nothing.
 * There is a special type of robot in Gnomeregan that has the ability to put up a shield that reflects magic back to the caster. Spell users should watch for it and hold off on their spells until it disapears.
 * The Dark Iron Agents who appear near the end of Gnomeregan are very well some of the deadliest NPCs there. They will drop land mines every now and then. When you see these land mines, Disable These Immediately By Attacking Them!  They have only 200hp, but they inflict over 400 damage on everyone nearby. Assign someone to destroy them and make a macro to target them.
 * There is a Backdoor into Gnomeregan. The door is unlocked with the Workshop Key carried by the Electrocutioner 6000. The lock can also be picked by a rogue. The backdoor is inside the Train Depot near Techbot - just walk straight forward instead of turning to the left. On the other side of the first big room, the back door is ready to be opened.
 * If you are part of the Alliance you and your party can rest safely in the Clean Room; you can sell picked up and Sparkle-o-matic items to a local merchant, or even mail items to others at the mailbox.
 * It may take a longer time to get a group for Gnomeregan together, as many people do not like to run this instance.
 * This instance is very rarely run by Horde groups, and some of the dropped items are coveted by level 29 twinks, which makes some of the BoE drops in there, as well as the Discombobulator Ray very lucrative on the Auction House.
 * Binary punch card translations: The blocks of 1s and 0s that appear in the description page when you interact with different machines actually have meaning. They are binary representations of ASCII text.  A few examples listed here:
 * Recipe: Mechanical ChickSoup
 * Gnomercy!
 * A few examples from Thottbot:
 * Tell your friends to play WoW
 * Play the Warcarft roleplaying game
 * Kiss me, I'm gnomish!
 * The Lich King lives!!!!!!!!!!!!!!!!!!!!!!!!!
 * Gnomeregan forever!
 * How am I driving?
 * Thrall and Jaina sitting in a tree, K-I-S-S-I-N-G
 * If you can read this, you're standing too close
 * The gnome king wears night elf underwear
 * Help! I'm trapped in a binary punch card factory!
 * Message to Castpipe: your laundry's ready for pickup.
 * Message to Castpipe: your laundry's ready for pickup.