It started last OCTOBER 29, 2011.
House theme
For the Unlimited season, the exterior of the House has been slightly tweaked to have slotted walls and minor modifications, but still keeping the yellow and blue color scheme. There are four areas for this season: three Houses and a special area.
Slums: The first house which was first occupied on opening night was made to look like a typical squatters' area in many urban areas in the Philippines. This was done to let the housemates experience the same living conditions as 15 million Filipinos who live in such areas, based from a typical answer during auditions of experiencing typical Filipino life.[14] This House was demolished on Day 22.
Industrial House: The interior of the second House follows the regular House layout and its accompanying amenities. It is further given an "industrial" feel with steel, wooden, and brick walls. Unlike previous seasons, however, this House has no yard area.
Luxury House: The third House is exquisitely furnished and brightly lit. Like the Industrial House, this House also has no yard area, although sunlight somehow passes through a curtain.
Resort: This area is sophisticated with the inclusion of the pool and a jacuzzi in the beach-themed Garden area. It's used as a rewards area, a task area or an area for special occasions.
Unlimited twists
Reserved housemates - Aside from the thirteen official housemates who entered in Day 1, and an unknown number of secret housemates sequestered in a secret location, thirty short-listed housemates are given another chance to become official housemates. A lottery is made on Day 1 to choose the sub-official housemate. On Day 15, six reserved housemates entered; three girls collectively known as the 3Gs entered the Slums while three boys collectively known as the Power Strangers entered the Industrial House. Another two male reserved housemates entered on Days 23 and 25. They will be given tasks to fulfill in order to become official housemates.
Unli-Day/Unli-Night - Like the previous regular season, Double Up, it was announced that there would be two houses, each containing a different set of housemates. To accommodate both, a second main program will be launched and aired in the afternoons to focus on the events in the Industrial House to be hosted by Bianca; the original primetime main program hosted by Toni will continue to look into happenings in Slums (now Luxury House). The programs will be dubbed as Unli-Day and Unli-Night respectively. This only applies to weekdays; on weekends, nomination and eviction nights, and special shows, the primetime program would cover both Houses.
House Swaps - Housemates were made to swap houses and group members as instructed by Big Brother.
S-E Voting System - Also lifted from the previous regular season, the Save-Evict voting system gives a chance for the public to vote to save or evict a housemate. The housemate with the lowest net votes, Save and Evict votes combined, is evicted. Furthermore, voting for each house's nominees are separate yet simultaneous for every week, thus having two evictees per eviction.
House Competitions - Big Brother brought back the House competitions from Double Up, but with a more lucrative prize. For ten weeks, the Luxury House housemates, dubbed as Team High Voltage, would compete against their counterparts in the Industrial House, known as Team Wayuk, in weekly major competitions with P150,000 at stake in each. At the end of those ten weeks, the cash accumulated by each team would be shared among the final four housemates in each House. The teams would also compete in "mini-battles" wherein the winning team would experience minor rewards.
It started last OCTOBER 29, 2011.