Rabbit hole

A rabbit hole is an object, generally in massive size, which Sims can enter or do activities in, but players are unable to see what's inside it. Rabbit holes fade away when the camera gets closer to them, and Sims cannot be seen what they're doing inside one.

Functions
Most rabbit holes function as workplaces where Sims are employed and work in. Most of them are building-sized, though some of them are not, such as mausoleum, gypsy caravan, or arboretum. Sims can perform various activities inside rabbit holes, such as getting employed, attending a show, attending a class, and so on. Some rabbit holes render the lot assignment of community lots. Rabbit holes placed in a community lot will also replace the lot's map tag with the rabbit hole's map tags.

Some rabbit holes are investable. Sims can become partner and own them. Once Sims become an owner, they can rebuild the lot to improve it to become more attractive, rename the rabbit hole, and also fire Sims at their will. They can't, however, fire the last employee who work there.

In some careers and professions, some of their duties or opportunities are to enter certain rabbit holes to perform something. What they do doesn't really matter, because they will just enter the rabbit holes and complete their tasks themselves. For example, Firefighters sometimes have a building disaster where they'll enter a rabbit hole and complete it eventually.

Although rabbit holes will fade when the camera gets closer, players can see the contents inside them with cameraman view by pressing the Tab key. Everything inside the building is 2-D decorative textures that serve to make the rabbit holes or buildings more realistic when players peek them through window from the outside. Environment sounds and music can be heard when Sims are inside the rabbit holes. Usually it's a sound effect related to the rabbit holes, such as school bell at school or eerie voices at mausoleum, with an audible background music.

Autograph session
Sims who are at their top of certain careers can hold autograph sessions in some rabbit holes. While in autograph session, Sims must give autograph to as many visitors as possible. The more Sims get autographs, the more the player will earn money. Sometimes, this will also attract and advertise Sims to enter the rabbit holes to watch show or game for example, which will give bonus as well. Technically, Sims can hold autograph sessions in rabbit holes where Sims can enter to attend a show, i.e. theater, stadium, equestrian center, or film studio.

Additionally, Sims can also make an advertisement deal with bookstore and supermarket. This is simpler as Sims only need to enter the rabbit hole in an amount of time, and they'll earn money. Sims need to wait for a week to make another advertisement deal. Sims cannot have two deals at a time; which means they need to wait for a week to make a deal in supermarket if they've made one in bookstore.

Multi-purpose rabbit holes
Since Late Night, some multi-purpose rabbit holes are present to preserve neighborhoods that lack enough space for big lots, such as Bridgeport. Although this seems practical, there are some issues regarding with multi-purpose rabbit holes, such as the inability to complete opportunities that are related to rabbit holes. Sometimes, the option to perform task from opportunities is not available, which prevents player from completing the opportunities. For example, the aftershool activities-related opportunities cannot be completed at school in Moonlight Falls.