Masou Gakuen HxH.
Warning 1: It's kinda trash.
Warning 2: There's no plot, only plot.
Warning 3: Depending on who you ask, it may or may not be hentai.
Warning 4: Do not watch it with your wife.
Warning 5: Or anyone, really.
For an actually good show this season, I'd recommend Amaama to Inazuma or Orange.