This is just an idea, but depending on a topic I would bring pre-prepared sheets of coloured paper with drawings that you can combine.
For example, let's talk about US History: You take a map and you cut out the shape of a colony, and then when you talk about the changes, you stick over it a piece of paper with a new shape.
biology? bring pieces of papers that you can put together as a "puzzle" to make an organ or a cell.
governmnet? cut out pieces of paper that symbolise the structures and arrows to show relations between them
