Everyone teaches coordinates, and these are the three lessons I did with my class just before the end of term.
First of all, battleships. This is usually played in the spaces between lines rather than on the intersections of lines, so I adapted it to be more like Descartes would have wanted:
Here we are playing. (Somehow the logistics of playing two games at once, and marking what you're attacking as well as what you're defending was a tiny bit confusing for some children.)
I took the same grid and suparimposed it on an aerial photo of the school, so that we could do a coordinates treasure hunt game.
One player writes down the coordinates of where they've "hidden" the treasure. The other player then guesses where it is, giving coordinates. If they're right next to it ("hot") they're given a red cube, if they're a bit further ("warm") a yellow cube, and further away still ("cold") a blue cube.Desmos to draw something by entering the coordinates. My stipulation was that their designs should "go round in some kind of circle sort of thing". It didn't matter what, as long as it returned to the start again. This, I think, took the pressure off thinking too hard about exactly what to draw. I especially like this for the freedom it gives, and the instant feedback on how you're doing!