I've been reading Neptune's Brood by Charles Stross, which takes place in a posthuman future where the civilization of humankind's android/bioroid creations have spread out into the stars. These beings can look pretty much human and act pretty much human--including eating and excreting biological material. The difference is that they are made of mechanocytes instead of biological cells that must "learn" to form organs and "tissue" types and their brains have soulchip backups they can be placed into a new body if their old ones are destroyed. Interestingly, priests (like those of the Church of the Fragile, who seek to disseminate old style "fragile" humanity in the galaxy) have "powers." Special structures and training that allow them to control the mechanocytes of others to heal or alter forms.
All of this sounded like a good way to in-setting rationalize traditional dungeoneering rpg tropes, if you're into that sort of thing. Imagine a future where humankind is extinct and its android descendants live in a pseudo-medieval society--except for things like soulchips (or something of that nature) and clerical healing. The androids (who would just think of themselves as "people," of course) would go down into the underground ruins of old humanity (who they probably wouldn't realize were any different than themselves) to wrest treasures from less socialized posthuman intelligences, i.e. monsters.
What would be the point? Well, it would be an interesting mystery to add in the background of a science fantasy sort of campaign (like a variant Anomalous Subsurface Environment, maybe). Also, the increased durability and easy resurrection of posthumans would explain some things about how D&D works as written, but could also be used to ramp up the carnage to Paranoia-type levels. Death wouldn't necessarily mean starting with a new character most of the time, it would just mean starting with the same character, poorer than before or owing a debt to somebody.