<telerik:RadGrid ID="RadGrid1" runat="server" AllowPaging="True" Width="800px" RenderMode="Lightweight" OnNeedDataSource="RadGrid1_NeedDataSource">
    <MasterTableView AutoGenerateColumns="False">
        <Columns>
            <telerik:GridTemplateColumn>
                <ItemTemplate>
                    <telerik:RadMonthYearPicker ID="DatePicker" runat="server" RenderMode="Lightweight">
                        <MonthYearNavigationSettings TodayButtonCaption="Heute" />
                    </telerik:RadMonthYearPicker>
                </ItemTemplate>
            </telerik:GridTemplateColumn>
        </Columns>
    </MasterTableView>
</telerik:RadGrid>

protected void RadGrid1_NeedDataSource(object sender, Telerik.Web.UI.GridNeedDataSourceEventArgs e)
{
    (sender as RadGrid).DataSource = Enumerable.Range(1, 6);
}

<telerik:RadMonthYearPicker EnableAriaSupport="true" EnableKeyboardNavigation="true"  ID="from_date" name="from_date" runat="server" RenderMode="Lightweight" 
            Width="150px" ToolTip="" Height="40px">
            <DateInput ID="fd_input" DateFormat="MM/yyyy" runat="server" Enabled="true">
            </DateInput>
            </telerik:RadMonthYearPicker>
            <asp:RequiredFieldValidator runat="server" id="v_from_date" ControlToValidate="from_date" ErrorMessage="- Required" CssClass="validator" />
            <asp:RegularExpressionValidator ID="reg_v_from_date" runat="server" ErrorMessage="Invalid From Date" ControlToValidate="from_date" Text="Format: MM/YYYY" ValidationExpression="^\d{4}-\d{2}-\d{2}$" CssClass="validator"></asp:RegularExpressionValidator>

<table runat="server">
    <tr>
        <td>Month/Year:</td>
        <td>
            <telerik:RadMonthYearPicker ID="MonthYear" runat="server" Width="150px">
            </telerik:RadMonthYearPicker>
        </td>
        <td>
            <asp:Button ID="btnGenerate" runat="server" Text="Get Report" OnClick="btnGenerate_Click" />
        </td>
    </tr>
</table>

 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            MonthYear.SelectedDate = DateTime.Today;
            MonthYear.MaxDate = DateTime.Today.AddDays(1);
        }
    }