Co-ordinates in Maths

You can create a line graph here        
http://nces.ed.gov/nceskids/graphing/line.asp         
You need the [x, y]

Another lesson    
http://student.ccbc.cc.md.us/courses/math083e/lecture/review/review0.htm

Simple coordinates worksheet
http://www.shodor.org/interactivate/activities/pcoords/worksheet.html

Simple coordinates game  
http://www.shodor.org/interactivate/activities/pcoords/index.html

Simple maze game worksheet
http://www.shodor.org/interactivate/activities/pmaze/worksheet.html

Simple maze game    
http://www.shodor.org/interactivate/activities/pmaze/index.html

Have a go at this game by putting in the coordinates ... avoid the mines http://www.shodor.org/interactivate/activities/coords/index.html
it's at the bottom of the page.

Another game using grids
http://www.mathsphere.com/Resources/documents/bingoco.pdf
 

A lesson plan using a game  [battleships].       
http://mrskingsbioweb.com/Cartesian.htm
Online battleships - to get the idea 
The best one I think

Then you need to make up your own!      
http://www.activityvillage.co.uk/battleships.htm

Another battleships lesson
http://www.lessonplanspage.com/MathBattleshipPlotCoordinates79.htm

Battleships is a traditional game for two players, who will each need a paper and pencil.

First draw a grid about 8 squares tall and wide. Label the grid with the numbers 1 to 8 along the bottom and letters A to H along the sides. Make sure that each player’s grid is the same! Then, making sure that the other player cannot see what you are doing, mark “your fleet” onto your grid. An aircraft carrier is five squares in one straight line; a battleship four squares in one straight line, a cruiser three squares in one straight line. Each fleet should also have two destroyers (two adjacent squares) and two submarines (single squares). Now try to find your opponent’s fleet by calling out a position on the grid (eg D4 or H8). He must tell you whether you have a “hit” or a “miss”, or if you have sunk a craft (and if so, which craft it is). The first player to sink his opponent’s fleet is the winner.

If you would prefer not to draw your own grids each time, you can find a free printable version of Battleships at Activity Village, here:

http://www.activityvillage.co.uk/battleships.htm

http://www.funorama.com/images/battleships.gif

Have a look at this one in "Quiet Games"

Another Game similar to "Battleships" 
http://www.pnwboces.org/outdoor/NY_Jason/Battleship_Game.htm

Another lesson plan  
http://score.kings.k12.ca.us/lessons/graphing.html