Soporific
Definition: something that induces sleep
From the Latin “sopor” which means “deep sleep.”
Why I Looked It Up
From the novel Reamde:
The inherently soporific nature of software installation has its way with her, and she closed her eyes and then opened them to find it was daytime.
Update
Added on
In Information Hunters, the book refers to a group of people known as “The Office of Soporific Sinecures,” refering to their tendency to sleepwalk through their cushy jobs.