"Hyouka" had a pretty uninformative and general description. Oreki Hotarou has just entered high-school. He is almost typical boy, except for his philosophy - he is an "energy-saving boy" and his motto is: "If I don't have to do something, I won't, but if I have to, I'll do it quickly.". Meaning, he avoid any unnecessary effort and obligation, even though he is not lazy. According to his life-style, he would avoid joining any high-school clubs, because it would ask for additional effort, but he is forced by his older sister to join Classic Literature Club. There he meets Chitanda Eru, also from his year, who is a very curious and dynamic girl - his complete opposite. Later they are joined by Fukube Satoshi, Oreki's best-friend, and Ibara Mayaka, a friend from their junior-high school.
Plot of "Hyouka" stems from Chitanda's curiosity (her phrase is "I can't stop thinking about it") and Oreki's uncanny ability to connect seemingly uncorrelated facts into a theory or explanation. It turns out that Oreki is a natural born detective - when he can be coerced to leave his usual low-energy state. There is no overall plot in this anime, only a bunch of standalone episodes and three mini-arcs made of two or three episode. At the beginning, I was wondering why this anime got an award in Slice-of-Life category when it was clearly a detective anime, but toward end focus shifts more to characters and their daily life than to plot.
Also, a word of advice. This anime has a pretty slow introduction, so give it some time to really start. It you like it when it reaches Seikitani Jun arc, things go only better from that point on.
From my description, you probably understand that I liked this anime, although it doesn't sound like anything extraordinary. And this is true, this anime is not extraordinary - but it is very, very good in every aspect. There is no big story here, but each episode and few arcs are very interesting, even if you don't like detective stories (I don't, really). Characters don't stand out, especially at the beginning, but they grow more complex and life-like whole time during this show. Animation and design also don't look anything special at first glance, but as you watch it, you will realize that a major effort is put in details and that everything fits right. There is also some romance, some comedy and much of light humor. Looking back now, this anime is like normalized (in sense that both high and low extremes are flatted out) "Haruhi Suzumiya" show. And I think that fans of it will also like "Hyouka". Despite slow and unimpressive start, this show ends as one really good anime.
There are some unexpected quirks in this anime. First, you rarely see a minor getting drunk in anime (even when it is accidentally). Secondly, it is not common that boy is attracted to girl only psychically (at least at first), except in ecchi anime. It usually involves unrealistic romance (e.g. Harima and Tenma from "School Rumble").
All in all, even not extraordinary, "Hyouka" is quietly great anime and I would recommend it to anybody who doesn't require action from anime their watch. It is interesting, sometimes mysterious, lively and fun all the way.