Weekly Challenges are a harder version of daily runs and give better rewards, they have boss rooms and a few regular rooms.

Examples I've made are, figure rooms: Library, electrical room, with regular rooms between them. Chases: hotel seek, eyetsalk, mines seek, sewer seek with some regular rooms between them. Large boss rooms: hedge maze, the nest, the dam, with some rooms between them.

New rooms: 

outdoors to nest: a small cavern room with a lake that comes from outdoors and leads to the nest, when Opening the door to the nest queen grumble chases you and it continues like the original except you go through the normal blocked off part under the minecart track and it is still accessible after the cutscene.

mini jeff shop: it shows up after door 151 that is after the nest and it leads to the dam.

Mini courtyard: a small version of courtyard that has a small version greenhouse attached

Fall down to mines area: you fall down from the top of that ravine in seek mines start

Layouts:

Figure one: elevator: library, after library room, pre courtyard room, greenhouse, electrical room, small minshaft with exit.

Chases one: elevator, hotel seek, pre courtyard room, mini courtyard, mini greenhouse, outdoors start, outdoors room, outdoors room, eyetsalk, eyetsalk to mines ravine thing, mines seek, mines seek end room but u exit Minecart, mines to sewer transition, sewer seek, end room.

Bramble grumble dam seek one: elevator: hedge maze, outdoors to mines cutscene, cavern room, the nest(with that cavern accessible), 151 room, mini jeff shop, the dam, end room(behind the generator door)

The rift in the electrical room can be interacted with but doesn't work, using it gives you a bagde called "1NT3RRC0N3CT3D"

you can get crucifix badges from the weekly runs for outdoors entities.