forward ExpTimer();

public OnGameModeInit()
{
    SetTimer("ExpTimer", 60000, true); // Repeating timer set when the server starts up
}

public ExpTimer()  // The timer callback
{
    for(new i = 0; i != MAX_PLAYERS; i++)
    { // Loop
        if(IsPlayerConnected(i) && !IsPlayerNPC(i)) // Checks if player is connected + NPC's don't need experience
        {
            GivePlayerExp(i, 15, ""); // Every connected player receives 1 EXP
        }
    }
    return 1;
}