Clannad Nerds FTW
Fuko is tricky to find all the scenes of her but her main arc is episodes 4-9. The reason she is tricky is that she just shows up at random points through out the rest of the series every couple of episodes to help out but always ends up failing, some of those scenes happen in episodes 12, 15, 17, 18, 20 (I am pretty sure that is all of them). All of those scenes are very short and she is there mainly as comedic relief. I would make sure you find at least one of the first couple ones because she will have this great intro that makes her look like some kind of Mahou Shoujo being summoned.
Fuko also has a role in After Story, she will be be in episodes 19 and 20. She also is in the very last scene of the entire series, the end of episode 22 (awesome Clannad trivia: the scenes for the start of the opening theme for Clannad all come from that very last scene of Clannad Afterstory)
Zanz Bonus Points Tally
8bit_samurai: 1, CodeZTM: 1, Eake4: 2, ibabrak: 5, Mirkosp: 4, tipsd9video: 1, uncreative: 1