I just finished this book.. I thought it was really good.. I thought some other people might like it, and I could tell about it a little. =)
It's called 11 Birthdays.
And basically its the main character's birthday, Amanda. She is turning 11, and just can't wait to get her birthday over with. She goes to bed that night, and wakes up the next day, which is Saturday. But its not - Its her birthday all over again. She has to figure out how to get her birthday to stop.
It was really good.. I just finished it!