Dummy Corp is a secret facility controlled by the Office of Secret Intelligence on The Venture Bros. It contains classified information held only in hard copy form because the OSI is too paranoid and old-fashioned to store it electronically.
In The Rorqual Affair, Red Death, Dr. Mrs. The Monarch, and Henchman 21 broke in to find information on the location of Douglas Ong, who was under OSI protection, in order to save the Monarch from the wrath of Wide Wale. Red Death murdered many people inside, and the ensuing clean-up caused the OSI to be unable to provide back-up for Brock Samson when Jonas Venture Sr. gained control of VenTech Tower in the episode Arrears in Science.
By the episode The Unicorn in Captivity the location of Dummy Corp had moved to an unspecified floor within VenTech Tower. Brock Samson brought Dr. Venture there to speak with Hunter Gathers upon Doc's groundbreaking invention of a pair of teleporters.