Yesterday I used masking tape to turn the floor of my classroom into a coordinate plane.
Students had to graph themselves, then find the slope of the line between themselves and various other points in the room. A good time was had by all, and a few insights were had. Today I think we will also graph all the bits of trash that usually get left on the floor by lunch time. That will give us time to set up for a fierce game of Coordinate Plane Battleship. Oh, the things we do to promote a deeper conceptual understanding! :)