Azumanga Daioh is about high school life through the eyes of six girls with unusual personalities: Chiyo (the 10-year-old genius), Osaka (the resident airhead), Sakaki (the shy one prone to cat bites), Tomo (the loose cannon), Yomi (the short-tempered one) and Kagura (the resident jock).
If you're looking for a filler anime, then this is perfect. The story revolves around six girls and their everyday lives, but it's the personalities of these girls that makes the anime a really great watch. Each girl is different and each character adds to the story in some way. The dialogue isn't too bad and there are lost of funny and touching moments between the characters. It's a really simple anime but it's great for passing the time.