hey there! This is my first challenge idea so I hope you enjoy!
There must be 4, 6, or 8 sims in total depending on if you want pets or kids or anything. I recommend 6.
They'll live in a Custom built 4-bed house
There can be a Pool and hot tub
Aim- Create a reality show with your young adults, I recommend you have a mod for over 8 Sims. Pets are optional
You Can leave lot and you control all sims.

You Must have at least 4 dramas (can be same, no more than two of each)
-cheating (one member of a couple catches the other)
-major breakup + get back together (speaks for itself, can woohoo with other sims between these events)
-death (obvious- must have kid/pet to fill gap)
-kids (mute sound during try for baby/risky woohoo, end up with child. Need death/mod/. Or have kid during affair while in another relationship)
-lady’s man (one guy woohoos with all girls- must get at least one pregnant)
-Guy's gal (one girl woohoos with all guys, must have at least one child)

Rules
All have to have flirty trait and family oriented and irresistible if possible
Must have at least two long term couples during the whole thing but they can break up
At least one marriage
At least one affair
At least one child
A guy can have kids with more than one female and vice versa
Can only date people from in the house
After babies become toddlers, parents can have other affairs as well

House necessities:
8 double beds
Four bedrooms
Four en-suite bathrooms
At least one living/TV room
Basement
At least one bar with stools
Bookshelves, computers, and other skill building things are optional

Off of one side of the house, you must create a studio apartment at first, which can grow if you have more kids. when a sim gets pregnant, lock her and the father in the studio apartment. When the child is born,the father may leave but the mother has to stay until it becomes a child. In this time, she may invite other male sims in to create more children and you can lock one female in there for child bearing purposes only if you wish. the children must stay in there until they can move out. Lock the door so that only the kids can get in.

You can basically have any number of sims to start with as long as they are equal parts boy and girl if you want an odd number, add a genderfluid person but change their traits and don't let them reproduce.

Have fun!!!