The Secret Warehouse is a room which can be built by the player in the Basement of Strangetown Hotel in The Sims 2. Located inside is a fortune teller machine and a bench, as well as skillpoints at various points throughout the week.
In addition, Bigfoot can be found inside, a unique type of character. Upon interacting with him to the point where he's your sim's best friend he can venture outside of the Secret Warehouse. The price of 2000 simoleons to build the room is likely due to the fact that a new character is unlocked. Despite it's high cost, the Secret Warehouse adds only 4% onto your hotel score.