In ancient China, women bind their feet for cosmetic reasons, resulting in them not able to walk without help and walking in a shuffling gait.
Possibly this can be modified such that people do it for less stupid reasons.
Disclaimer: This is NOT a racist remark since I'm Chinese myself and hence entitled to freely judge Chinese customs. NOT sexist either since I'm female as well.
This really comes from an ancient Chinese novel. Imagine during the PCs' travels, they come to a place where the gender roles are completely reversed. What adventures will the PCs encounter in such a place?
A sentiment weapon that is very impressionable in terms of what is right and wrong, akin to a child. Currently, being ownerless, it is not very powerful. However, once it has found an owner, it can provide significant boosts to the wielder in an area or areas the wielder most desire. What adventures will this sentiment weapon go through? How will it develop itself in terms of power and personality?
As Moses turned away from the flaming bush, and made his way back down the mountain, IX-92 shut down the hologram and warped back to the future.
Artificial Intelligence was the pinnacle of human achievement, and IX-92 was their final series of Hunter-Killer Warbots, designed to exterminate the foe and any it deemed a terrorist.
In the end, IX-92 evolved itself and even all aspects of human society, and as time went by humans could enjoy life more and not work any longer.
200 years went by and humans worship god and his angels, while ever fearing the dread demons of Lucifer.
IX-92 are both angels and demons, depending on which side you are on, and to them humanity is a species of servile dogs that have outlived their usefulness.
They travel through time to push humanity in the direction it needs to be pushed, until the day, 2077, when humanity no longer is in control of their own destiny.
Yes, God could hear your prayers.
But God didn't care.