1. DIY makeouts (The Sims 2 - 2004 - PC)
The Sims 2 isn't just one of the most popular games in history - it's also considered one of the most family-friendly. Hell, our mothers play this game. So when you think "The Sims," you probably don't think "hot lesbian kissing." But you're wrong.
See, The Sims already has a pretty creepy premise, what with the player creating little people and then ruthlessly micromanaging every aspect of their lives like some barking overlord. It gets slightly creepier - or sexier, if voyeurism is your bag - when you discover that you can make your digital pets get it on, more or less, with whomever you want them to.