Greenglass House
This book is a New York Times bestselling middle grade level book (like Harry Potter, or at least the first few Harry Potters) that won the Edgar Award for best Juvenile Mystery. To my thinking, it is the classic cozy read. Tween Milo lives with his parents in a bizarre old hotel that is frequented by smugglers. He's looking forward to his holiday break, as the hotel is usually quiet this time of year. The snow is falling, hot chocolate warming on the stove, and he's almost finished up his homework when not one but five guests arrive. There's definitely something funny going on, and Milo and his friend Meddy invent a role-playing game to help them discover the odd guests' secrets.