Arboretum

The Arboretum is a rabbit hole featured in The Sims 3: Supernatural. Sims can tour the arboretum and WooHoo inside this rabbit hole. The only pre-placed arboretum in the game is located at Fae Ray Garden in Moonlight Falls. Inside the arboretum, Sims can also enter gardening competition, search for fairies, play fairy games, and talk to baby's breath.

Gardening competition
Sims can enter a gardening competition inside the arboretum. They require at least one harvestable in their inventory. The contest begins at 12 PM to 3 PM, and lasts for 3 hours. Virtually, up to 12 contestants compete in the contest. Multiple Sims in the active household can enter the contest together. Fake contestants will be generated by the game only to fill the empty slots to simulate competition rankings.

Upon entering the competition, the game will find the best quality random harvestable and remove it from the Sim's inventory. The quality of the fruit determines the competition score, but not the type of the harvestable. It means that a perfect apple will have a greater score than an outstanding Life Fruit. Aside from the harvestable quality, the number of Gardening skill points (or Child Gardening for children) also determines the competition score. Sims will be disqualified if they leave the arboretum while the competition is still in progress.

The exact competition score calculation is as following. First, the quality is multiplied by the quality multiplier. Then it's added to the total of Gardening skill point multiplied by skill point multiplier. If the contestant is a child, the Gardening skill point is randomized between 0 and 10, and in addition, they will also get a Child Gardening skill point bonus added to the score total. Finally, the score total is multiplied by a random number between 0.75 and 1.5, which is then used to determine the contestant's score. The multipliers for children are generally higher than adults, so children have higher advantage in winning the competition.

Sims will be awarded money if they earn the 1st to 8th place. Additionally, the 1st place winner will be rewarded a Gardening Competition Trophy in their inventory.

Search for fairies
Searching for fairies may trigger a special opportunity for Sims to become a fairy. There is only 4% chance that this opportunity will be triggered after they enter the arboretum.

Play fairy games
Children, Sims with Childish trait, and fairies may enter the arboretum to play fairy games. They will spend half an hour inside and get the "Played Fairy Games" moodlet.

Talk to baby's breath
Sims who are either mummies or SimBots can talk to baby's breath inside the arboretum. They will spend an hour inside and get the "Magic in the Air" moodlet. This moodlet increases the chance of conception and random occult mutation of a baby by +50%.

Trivia

 * Both "Fae Ray Gardens" and "Fae Ray Arboretum" are references to the actress Fay Wray.
 * When looking inside the Arboretum, only flowers and plant decorations can be seen.