Countdown in game..?

Does anybody know of a way using logic bricks to basically count down from say 6 minutes or so for a game so after 6 minutes it switches to a diffrent mode of the game.

oh and i tryed using the delay sensor and set it for 3600 witch is 1 minute but i cant do like 7200 for 2 minutes and so on because it wont let you set it past 5000.

cool thanks! i saw this yesterday but i thought it was something kinda diffrent but this will work!