I gotta look around if they have any interesting challenges for the Sims 4.

I also adore the clubs they added in the Get Together expansion. You can literally make anything you want. You can have a group of people that will just meet up to smurf in public places - and they will do it without knowing each other enough, because you set it as a rewarded club activity. Or you could establish a gang of old people who devote their free time to attack any and all teenagers they see. Really, the possibilities are endless