Hi,

You can try the below sample with Ajax Timer.

    <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional" >
        <ContentTemplate>
            <asp:Timer ID="Timer1" runat="server" Interval="3000" ontick="Timer1_Tick">
            </asp:Timer>
            The server counter is:<asp:Label ID="Label1" runat="server" Text="0"></asp:Label>           
        </ContentTemplate>
    </asp:UpdatePanel>
    <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional" >
        <ContentTemplate>
             <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />           
        </ContentTemplate>
    </asp:UpdatePanel>

    protected void Timer1_Tick(object sender, EventArgs e)
    {
        if (Application["polling"] == null)
            Application["polling"] = 0;
        Label1.Text = Application["polling"].ToString();

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        if (Application["polling"] == null)
            Application["polling"] = 0;
        Application["polling"] = int.Parse(Application["polling"].ToString())+1;
    }

 You can also store the counter into the database.

The below links are about polling system.

http://www.scriptlance.com/projects/1215631785.shtml

http://www.dhtmlgoodies.com/index.html?whichScript=ajax-poller