Hm.
I'm not 100% sure but I think Steins;gate is seinen, Penguindrum might be as well. Neither of them are based on manga, so there's not really an official demographic for them.
Nichjou and Kamimemo are officially shonen, but considering the first episode of Kamimemo is about teenage prostitutes I'm not sure why it's not seinen
Usagi Drop is actually josei, but it's awesome.
Summaries might be more helpful:
Steins;gate: IMO, the best thing on the air right now. It's a thriller about time travel. It's way awesome.
Mawaru Penguindrum: There are two guys whose sister dies. Then she puts on a magic hat and is alive again. The magic hat has a personality that takes over her body and wants them to find an item called the Penguindrum. If I start talking more about it we'll be getting into spoilers.
Nichijou: Basically extremely over the top absurd comedy. Like Azumanga Daioh on crack.
Kamisama no Memochou: Detectives. NEET Detectives.
Usagi Drop: Main character's grandfather dies, he goes to the funeral and finds an unfamiliar little girl there. He finds out that his grandfather had a mistress and that the child is hers. Noone in his family wants to take care of her, so he does.