Hallie and Annie are named after Nancy Myers' children. Hallie plays a girl at Camp Walden who asks where one of the camp cabins is located, and Annie plays an employee at the Stafford Hotel who brings Elizabeth a First Aid kit
Lindsay Lohan's Mum, two brothers and sister were seen in the airport when she was doing her hand shake with the butler.
The street Hallie and her mom are walking across is a remake of Abbey Road, recreating everything from the people to the cars, etc.
At Camp Walden, when Marvas Sr. and Jr. get dumped in chocolate, the actresses were covered in real chocolate.
The hotel in San Francisco where they're all supposed to meet is the Stafford Hotel. In the original film, Stafford was the name of the boyfriend that twin Susan, playing Sharon, makes up to excuse talking to her mother about her father.
The director Nancy Meyers has her two daughters playing in this movie.