Natsume Yuujinchou

Natsume Yuujinchou (aka Natsume's Book of Friends) is a manga and anime series about a teenager named Takashi Natsume who can see spirits just like his grandmother could.  When she was younger, his grandmother bullied various spirits and bound them by taking their names.  When Takashi comes across her "book of friends" (the book with the spirits' names in them), he decides to do the right thing and free the spirits.

I've seen some of this show and it's pretty good.  I like the characters and the show has a pretty relaxed feel.  The second season of the show is currently airing in Japan.  You can watch the show online (both seasons) at Crunchyroll.