Pig City by Louis Sachar is a story about the rivalry of two clubs, Pig City and Monkey Town.
Laura Sibbie finds a hat with the words "Pig City" on it at a garage sale and wears it to school and all her friends wonder what Pig City is and decide it should be a secret club. To join the club you have to pay "insurance," which means putting something embarassing in a box to make sure you don't tell anyone about the secret Pig City club. If you tell, then your secret is revealed to everyone.
Soon a rival club, Monkey Town, is formed and the two clubs wage a "war" on each other by pulling pranks on like mustard in shoes, eggs in desks, etc.
Kids 8-12 years-old-old will love this book. It gets you hooked into how the kids form clubs and keep secrets and battle each other for supremacy.
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