Minecraft wiki entry for Traps, associated text: Lecterns can hold books, therefore, you could give a hint to someone about some important info, and set it up so as soon as they reach the sixth page maybe, the doors close, and TNT blows up the place. Don't set it to explode at the first page, they would go through the first few pages cautiously, and then feel safe, only to find out while they are reading the most important page, TNT removes them from the Minecraft world.