[Jeffry]

At TOP of your script:

pawn Код:

new Number=0;

Where you want to start the Timer (Mostly at OnGameModeInit):

pawn Код:

SetTimer("YourTimer", 20000, 1); //Timer gets called every 20 secs

The Function:

pawn Код:

forward YourTimer();
public YourTimer()
{
    switch(Number)
    {
    case 0: { SendClientMessageToAll(0xFFFFFFFF, "Case 0!"); Number++; }
    case 1: { SendClientMessageToAll(0xFFFFFFFF, "Case 1!"); Number++; }
    //....
    case 7: { SendClientMessageToAll(0xFFFFFFFF, "Case 7!"); Number=0; } // Make "=0" at the LAST case.
    }
    return 1;
}

I hope this helps you.

Greetz,
Jeffry