I am a HUGE fan of Katie Kazoo. This one is one of my favorites, I've read half the series. Katie Kazoo #33 is very humorous, Suzanne does pretty odd stuff.
Katie is at home sick in bed. She gets a call from Suzanne. Suzanne is bragging on how she has a calender with a holiday on almost every single day. Along the way Suzanne celebrates Umbrella Day, Wave All Your Fingers at Your Neighbor Day, Don't Cry Over Spilt Milk Day, Kite Day, Gumdrop Day, Toothache Day, and more, maybe. It all leads up to a switch.
I recommend this book.