"Raj: 'You said I could buy a desk.'""Sheldon: 'This isn’t a desk. This is a Brobdingnagian monstrosity.'"

In Jonathan Swift's novel Gulliver's Travels, Brobdingnag is the name of a land that is populated by a race of human giants "as tall as an ordinary spire steeple."

In Gulliver's first close-up encounter with the giants, he is attempting to get past a stile of which every step is six feet high when a group of field-workers approach with strides ten yards long and reaping hooks as large as six scythes.

Their voices he at first mistakes for thunder.

Swift's book fired the imagination of the public and within two years of the 1726 publication of the story, people had begun using Brobdingnagian to refer to anything of unusually large size.

(Swift himself had used Brobdingnagian as a noun to refer to the inhabitants of Brobdingnag.)

https://bigbangtrans.wordpress.com/series-4-episode-04-the-hot-troll-deviation/
http://www.merriam-webster.com/dictionary/Brobdingnagian