So you want a
[Thunderfury, Blessed Blade of the Windseeker]?
Here's what it's going to take:

Stage 1: Get Lucky

• Be the one person your guild agrees should get Thunderfury
• Loot one of the [Bindings of the Windseeker]
• About a 3% drop chance from Baron Geddon (left half) or Garr (right half) in Molten Core
• That's a 80% chance to drop after trying every week for 6 months
• Typically goes to the main tank (a Warrior)
• Tanks benefit from the threat Thunderfury generates, which benefits the group
• Main tank is most likely to be in the raid when the second half drops
• 1 in 20 people will go 50 runs without seeing one drop
• 1 in 100 people will go 75 runs without seeing one drop

Stage 2: Begin the Quest

• Bring your half of the bindings to Highlord Demitrian in Silithus
• Begin the quest [Thunderaan the Windseeker]

Stage 3: Gather the Materials

• [Elementium Ore] drops from Blackwing Technicians in Blackwing Lair
• Has about a 5% chance of dropping
• It shouldn't take too long for a guild to get ten of these

• 1 [Arcanite Bar] is crafted using 1 [Arcane Crystal] and 1 [Thorium Bar]
• Arcanite Bars are crafted with level 275+ Alchemy
• There is a 2 day cooldown to craft one bar (at least 200 days for one player to craft all 100)
• [Arcane Crystal] is mined from Rich Thorium Veins with a 3% drop rate
• [Thorium Bars] are easily acquired from Small and Rich Thorium Veins
• Arcanite Bars and Arcane Cystals can be purchased from the auction house (expensive, scarce)

• [Fiery Core] is commonly dropped from some elementals and one boss in Molten Core
• Can be purchased on the auction house (cost and scarcity varies)

• [Elemental Flux] is purchased from blacksmithing supply vendors and costs 15g each

• Kill Ragnaros in Molten Core and collect [Essence of the Firelord]

Stage 4: Smelt the Elementium

• Smelt Elementium Bar is learned from Master Elemental Shaper Krixix in Blackwing Lair

• Have a priest Mind Control Krixix to teach you the recipe
• Requires 300 Mining

• Smelt all of the materials you gathered in Stage 3 into 10 [Elementium Bar]
• Tip: It's wise collect both Bindings of the Windseeker before smelting the Elementium Bars

Stage 5: Get Lucky Again

• Get the other half of the [Bindings of the Windseeker]
• About a 3% drop chance from Baron Geddon (left half) or Garr (right half)
• That's a 29.9% chance both halves will drop after trying every week for 6 months
• Still probably going to the Warrior main tank; sorry Paladins, Hunters, and Rogues
• 1 in 20 people will go 121 runs without seeing both drop
• 1 in 100 people will go 175 runs without seeing both drop

Stage 6: Defeat the Boss

• Gather a full 40 man raid group
• Turn in the materials to Highlord Demetrian, completing [Thunderaan the Windseeker]
• Defeat Prince Thunderaan

• Collect [Dormant Wind Kissed Blade] and return to Highlord Demetrian

Stage 7: Did someone say
[Thunderfury, Blessed Blade of the Windseeker]?

• Thank your guildmates, don't /gquit
• Collect your reward!