event Calender in ASP.NET 3.5

<asp:GridView ID="gvcalendar"  AutoGenerateColumns="false" runat="server"  >

   <Columns>


   <asp:TemplateField ItemStyle-Width="200px" ItemStyle-ForeColor="red" ItemStyle-Height="100px"  ControlStyle-Height="100px" HeaderText="Sunday">
   <ItemTemplate>

   <%#Eval("Day1")%>





   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
    <Columns>
   <asp:TemplateField HeaderText="Monday" ItemStyle-Width="200px" ItemStyle-Height="100px">
   <ItemTemplate>


      <%#Eval("Day2")%>

   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
    <Columns>
   <asp:TemplateField HeaderText="Tuesday" ItemStyle-Width="200px" ItemStyle-Height="100px">
   <ItemTemplate>

   <%#Eval("Day3")%>



   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
    <Columns>
   <asp:TemplateField HeaderText="Wednesday"  ItemStyle-Width="200px" ItemStyle-Height="100px">
   <ItemTemplate>

    <%#Eval("Day4")%>


   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
    <Columns>
   <asp:TemplateField HeaderText="Thursday" ItemStyle-Width="200px" ItemStyle-Height="100px">
   <ItemTemplate>

    <%#Eval("Day5")%>


   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
    <Columns>
   <asp:TemplateField HeaderText="Friday" ItemStyle-Width="200px" ItemStyle-Height="100px">
   <ItemTemplate>

    <%#Eval("Day6")%>


   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
    <Columns>
   <asp:TemplateField HeaderText="Saturday"  ItemStyle-Width="200px" ItemStyle-Height="100px">
   <ItemTemplate>

    <%#Eval("Day7")%>

   </div>
   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
   </asp:GridView>

 In code behind 
by this way you can create your custom event  calender

you can bind the event data in rowdatabound event on a particualr date 
DataTable dtCalendar = new DataTable("calendar");

    string[] months = {"January", "February", "March", "April",   "May", "June", "July", "August", "September", "October", "November", "December"}; 
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            Session["DateTime"] = DateTime.Now;
            lblMonth.Text = DateTime.Now.ToString("MMMM"); ;
            gvcalendar.DataSource = GetDetails(DateTime.Now);
            gvcalendar.DataBind();
        }
    }

    public DataTable GetDetails(DateTime dtDate)
    {
        // creat an array of all of the months 

        dtCalendar.Columns.Add(new DataColumn("Sunday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Monday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Tuesday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Wednesday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Thursday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Friday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Saturday", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day1", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day2", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day3", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day4", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day5", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day6", typeof(string)));
        dtCalendar.Columns.Add(new DataColumn("Day7", typeof(string)));
        
        dtDate=GetFirstDayOfMonth(dtDate);
        DataRow myDataRow=null;

        int noOfdays = DateTime.DaysInMonth(dtDate.Year, dtDate.Month);
        int dayCount = 0;
        for (int index = 0; index < 6; index++)
        {

            myDataRow = dtCalendar.NewRow();
            for (int i = 0; i < 7; i++)
            {

                if (dayCount < noOfdays)
                {
                    switch (dtDate.DayOfWeek)
                    {
                        case DayOfWeek.Sunday:
                            myDataRow["Sunday"] = dtDate.Date.ToShortDateString();
                            myDataRow["Day1"] = dtDate.Date.Day;
                            break;
                        case DayOfWeek.Monday:
                            myDataRow["Monday"] =dtDate.Date.ToShortDateString();
                            myDataRow["Day2"] = dtDate.Date.Day;
                            i = 1;
                            break;
                        case DayOfWeek.Tuesday:
                            myDataRow["Tuesday"] = dtDate.Date.ToShortDateString();
                            myDataRow["Day3"] = dtDate.Date.Day;
                            i = 2;
                            break;
                        case DayOfWeek.Wednesday:
                            myDataRow["Wednesday"] = dtDate.Date.ToShortDateString();
                            myDataRow["Day4"] = dtDate.Date.Day;
                            i = 3;
                            break;
                        case DayOfWeek.Thursday:
                            myDataRow["Thursday"] = dtDate.Date.ToShortDateString();
                            myDataRow["Day5"] = dtDate.Date.Day;
                            i = 4;
                            break;
                        case DayOfWeek.Friday:
                            myDataRow["Friday"] = dtDate.Date.ToShortDateString();
                            myDataRow["Day6"] = dtDate.Date.Day;
                            i = 5;
                            break;
                        case DayOfWeek.Saturday:
                            myDataRow["Saturday"] = dtDate.Date.ToShortDateString();
                            myDataRow["Day7"] = dtDate.Date.Day;
                            i = 6;
                            break;

                    }
                   
                    dayCount++;
                    dtDate = dtDate.AddDays(1);
                }
            }
            dtCalendar.Rows.Add(myDataRow);
        }

        return dtCalendar;
    }

    private DateTime GetFirstDayOfMonth(DateTime dtDate)
    {

        DateTime dtFrom = dtDate;
        dtFrom = dtFrom.AddDays(-(dtFrom.Day - 1));
        return dtFrom;

    }


    protected void LinkButton1_Click(object sender, EventArgs e)
    {
        DateTime dt = (DateTime)Session["DateTime"];
        Session["DateTime"] = dt.AddMonths(-1);
        lblMonth.Text = dt.AddMonths(-1).ToString("MMMM");
        gvcalendar.DataSource = GetDetails(dt.AddMonths(-1));
        gvcalendar.DataBind();
    }
    protected void LinkButton2_Click(object sender, EventArgs e)
    {
        DateTime dt = (DateTime)Session["DateTime"];
        Session["DateTime"] = dt.AddMonths(1);
        lblMonth.Text = dt.AddMonths(1).ToString("MMMM");
        gvcalendar.DataSource = GetDetails(dt.AddMonths(1));
        gvcalendar.DataBind();
    }