Tomoya Okazaki is an ordinary high school senior who doesn't take his studies seriously. Always late for class, he's seen as a delinquent by the rest of his classmates, who are busily preparing for their college entrance examinations. He hates his life and the whole town, and the closest thing he has to a real friend is Loser Protagonist Youhei Sunohara, who just barely manages to rise to the level of Butt Monkey at the best of times. Tomoya is thoroughly miserable.
Then one day, while walking to school, he bumps into Nagisa Furukawa, a shy girl whose only friends at the school have already graduated. Whenever Tomoya sees her around school, she's alone; her classmates scarcely notice she exists, and no one has any interest in befriending her.
No one, that is, except Tomoya, who without even realizing it finds himself taking her under his wing. As he sets out to help her reestablish the school's drama club, he finds himself connecting (or, as it often turns out, reconnecting) with several other girls from the school. Although he doesn't care much about them at first — he doesn't much care about anything at first — he gradually opens his heart to them as they get to know each other better.
The title, according to the author, comes from the Irish word for "family" (although "Clannad" is actually the name of an Irish band, an abbreviation of "Clann as Dobhar" or "the family from Dore) — and indeed family, along with the related concept of True Companions, is a major theme of CLANNAD.
The original Visual Novel CLANNAD was made by Key Visual Arts and released in 2004. The manga adaptation, illustrated by Juri Misaki, was published by Jive between November 2005 and March 2009; Drama CDs were released in 2007. In September 2007, Toei Animation released The Movie, directed by Osamu Dezaki. The television series, by Kyoto Animation, aired between October 2007 and March 2008. The Visual Novel and the anime television series are each divided into two parts, the high school portion, which takes place during the first few weeks of Tomoya's senior year, and the After Story, which takes place later. Two special OVA episodes were made for this series by Kyoto Animation. The first is the bonus episode 24 in the first season, ''Another World: Tomoyo Arc'', and the second the bonus episode on the final Clannad DVD, ''Another World: Kyou Arc''.
(For those who care about such things: over at the Anime News Network, CLANNAD ~After Story~ (i.e. season two of the anime series) is currently ranked #1 among all 3000+ anime series and movies listed there — at least if you go by Bayesian estimator. It also previously held the #1 spot in a similar listing at MyAnimeList. Not that online polls are worth the paper they're written on. Still. Interesting.)
Both seasons and the movie are licensed by Sentai Filmworks, the employees of the once-prosperous ADV Films. The first two episodes are available online for free.
CLANNAD's Character Sheet can be found here; its Wild Mass Guessing goes here; its Fanfic Recs go here.
Not to be confused with the melodious friends and family of Enya.
So Ive heard about this before and have thought about watching it some time. How many people here would recommend it?