Trivia: The horse heart that Daenerys eats was actually made of gelatin, and genuinely tasted dreadful - her physical revulsion at eating it is real. It had dyed pasta to simulate veins, and was injected with fake sugary blood, which attracted flies. The blood was so sticky and ended up covering Emilia Clarke to such an extent that after filming it glued her to the toilet seat.
Trivia: Cersei remarks to Tyrion that she had heard his nose was cut off during the Battle of Blackwater Bay. This is a reference to the books, in which part of Tyrion's nose was indeed cut off.
Trivia: After the destruction of King's Landing, the white horse that Arya finds is the very same white horse that belonged to Strickland, the leader of the Golden Company. Note the horse's identical muzzle markings. (00:32:25 - 01:18:10)

Trivia: One of the severed heads on a spike is that of former president George W. Bush. Before shooting the scene, George RR Martin asked writers and producers David Benioff and D.B.Weis to have a cast of their 3 heads to be put on the spikes, but for budget reasons they opted to get a box from HBO's warehouse with used severed heads. They noted that one was Bush's, but they put a wig on it and got away with nobody noticing. In the Blu-Ray commentary the producers revealed the story, and got a lot of criticism from the right.
The Mountain and the Viper - S4-E8
Trivia: Towards the end of this episode, Tyrion and Jaime have a discussion about their brain-damaged cousin Orson. This is supposedly a swipe at Ender's Game author Orson Scott Card, who is a harsh critic of the show.
Trivia: The dead stag that the Starks discover was not a prop. Apparently it had been dead for two days, and the smell was revolting to the actors.
Answer: This is explained more in the book. Khal Drogo and his bloodriders do intend to help Viserys take the throne, however they do things in their own time. This is what causes Viserys's frustration. In the book, Illyrio Mopatis tells Viserys that he has already waited his entire life to claim The Iron Throne and that waiting a few more years isn't that big of a deal. The Dothraki are a nomadic tribe, which is largely why they have no interest in invading and sacking King's Landing. However, since Khal Drogo eventually grows to love Dany, her assassination attempt by the Westerosi compels him to seek revenge.
Phaneron