Sana often makes mention of the term komawari. Komawari is the practice of being able to move in small circles and change direction quickly. It also seems that Sana belongs to a group known as Komawari where she learned many skills to become an actress, such as being able to yell at inhuman volumes.
Kodocha is a contracted form of Kodomo no Omocha: the series original name. Funmation released it in America under this name as well. Often times you can see "Kodocha" written on certain things in the show if your quick enough to catch it.
Miho Obana is of course the manga artist who came up with Kodocha. Her first starring appearance was on the recap episode where she is one of the quiz contestants who only says "I'm Obana". But she continues to make various cameos throughout the show, like being on a TV program when Misako's book comes out, in the Kodocha intro, and marrying a popular actor among other things. You can catch her if you're quick to spot her pink kimono.
Towards the beginning of the series Sana makes references to someone named Peggy Hayama. While most of the people in America may not know this, Peggy Hayama is a famous entertainer in Japan. Whether Akito actually 'gets' these references, or just ignores them is hard to tell.
It's mentioned that Sana was named after the day she was born SAngatsu NAnoka (the 7th of March in Japanese). Sana is slightly distressed since she may have been born on the 6th of March which would be SAngatsu MUika, making her name Samu. Akito thinks this is funny since "Samu" is how you pronounce the name "Sam" in Japanese.
Also, when Sana decides that she wants to meet her little sister, she decides to meet her in an amusement park called "Ribbon Land". Ribbon is the name of a popular girls magazine which is a collection of comics targeted at girls. Kodomo no Omocha was a featured series in Ribbon.
When Sana needs help from Akito she decides to use the Buruccha to send him a coded message. Akito on the receiving end didn't know what to make of it so he whips out a book to help him decode the message. The title of the book flies by pretty quick, but it reads "Buruccha Code Even a Boss Monkey could Understand, by Sana Kurata". Note that Akito never made out the code.
Why someone would have a squirrel living on their head is a bit mysterious, but then again when you see Misako's hairstyle it doesn't seem that out of place. However it turns out that Maro being the resident in her hair wasn't intentional. Apparently when at a pet store that sold squirrels Maro got loose and got into Misako's hair. They couldn't get him out, so they had to buy him. Maro refused to live in any sort of pet house no matter how much they tried. Later on, even when Misako doesn't wear her elaborate hair pieces, Maro still likes to attach himself to her hair and hang off her braids.