Watching a pretty good one at the moment called 'The World God Only Knows', which is pretty funny. It's about a boy called Keima who is god of bishojo games (dating sims), but accidently signs a contract with hell to capture lost souls, which will involve him conquering girls in real life, not just in games. Obviously, he's going to use what he has learned from his games.

Like I said, it's pretty funny. Also, if you like the whole Otaku-love story type thing you will enjoy this.