The Westing Game is a mystery that is almost more of a puzzle. As the characters, 16 named heirs to an eccentric millionaire, are trying to solve the puzzle and find a murderer to get the millions for themselves, so are you. The heirs are full of character and any one of them would be amusing in and of themselves, but when you put them together, it's quite comical.
To say more of the plot would ruin it, but if this is a book you have not read, you're missing out. It's a light, fun read that I recommend to almost anyone 10 and up! (It does discuss murder and drunkenness, plus I don't know how much of the plot twists a younger child would understand.)