Are you talking about the Pinstar's 10 generation legacy challenge with the matriarch option?
https://forums.thesims.com/en_US/discussion/39862/the-legacy-challenge-rules/p1This challenge is the only reason I'm playing TS3. I purchased it shortly after it was released but quickly learned I couldn't control my neighborhood like I could in TS2. I quit playing for many many years. I finally decided to try it again after seeing this challenge. It has become such a blast!
I challenge my sims to not have any of the same careers as other sims (I keep track on a spreadsheet I found on here somewhere that also keeps track of the points on the challenge). Being forced to randomize their personalities has made it really interesting and let me see Sims I could never have created myself. They do things I totally don't anticipate! I hope you have fun with whatever you are doing.