An interesting idea struck me, today, on my way to class, possibly fueled by a lack of sleep, too many harem anime, and an odd comic from a little while back...
Ordinary, 20-something guy finds his life turned upside down when a pair of divine beings, a devil and an angel, decide that his soul is of incredible value, and begin to have a friendly duel over which side will claim him.
A simple premise, with many possibilities; perhaps the devil is a succubus, tempting him with herself, offering to fulfill all his sexual fantasies, while the angel offers love and companionship. Maybe both have been assigned to the job, but aren't terribly interested in actually completing it, although they can't return home until it's finished, and are forced to stay with him, leading to sticom hijinks. I definitely see this as lighthearted and amusing, drawing on a lot of anime influences. Wicked banter between the two beings, who are under orders not to actually fight one another, maybe even sexual tension between them, fueled by the lusty devil, not caring who she lays.
If you're interested, drop me a line, and we can hammer out some details. I'm willing to play either side, and maybe even turn it into a three-player game, if I get sufficient interest.