No matter what their native language is, people all over the world are familiar with riddles. From famous riddles in world literature to simple riddles that hint at everyday objects, there's something to suit everyone's fancy! So how can you incorporate riddles into your ESL classroom as a way to boost vocabulary and comprehension? We've collected eighteen of the best riddle resources from around the web to help you add some puzzling fun to your English language classes. Let's explore them together!