A really good idea to have a question wall as part of your classroom display, set aside for students to attach post it notes to.
I use it for History mystery exercises, students at the start of the lesson make a hypothesis as to what they think may have happened in an event. They can return to the wall at the end of the lesson or mid way through to change or add to their opinion.
Also useful if at the start of a lesson students write down two questions they still have about the previous lesson’s learning. You can then start your lesson by answering a number of questions and taking the opportunity to clear up any misunderstandings.
Exit questions can also be used as students leave the lesson, what do they think are the three most important things that have been learned in this lesson?
Endless possibilities and all you need is a pack of post its!