<div class="MenuItem">
  <asp:HyperLink ID="Menu1" NavigateUrl="HoverMenu.aspx" runat="server">Menu1</asp:HyperLink> | 
</div>      
<cc1:HoverMenuExtender ID="Menu1_HoverMenuExtender" runat="server" 
      PopupControlID="Menu1PopUpMenu" DynamicServicePath="" Enabled="True"  PopupPosition="Bottom" TargetControlID="Menu1">
</cc1:HoverMenuExtender>        
<asp:Panel CssClass="PopupMenu" ID="Menu1PopUpMenu" runat="server">
    <asp:HyperLink ID="Item1_1" NavigateUrl="HoverMenu.aspx" runat="server">Item1</asp:HyperLink><br />
    <asp:HyperLink ID="Item1_2" NavigateUrl="HoverMenu.aspx" runat="server">Item2</asp:HyperLink>
</asp:Panel>

<div class="MenuItem">
  <asp:HyperLink ID="Menu2" NavigateUrl="HoverMenu.aspx" runat="server">Menu2</asp:HyperLink>
</div>      
<cc1:HoverMenuExtender ID="Menu2_HoverMenuExtender" runat="server" 
      PopupControlID="Menu2PopUpMenu" DynamicServicePath="" Enabled="True"  PopupPosition="Bottom" TargetControlID="Menu2">
</cc1:HoverMenuExtender>        
<asp:Panel CssClass="PopupMenu" ID="Menu2PopUpMenu" runat="server">
    <asp:HyperLink ID="Item2_1" NavigateUrl="HoverMenu.aspx" runat="server">Item1</asp:HyperLink><br />
    <asp:HyperLink ID="Item2_2" NavigateUrl="HoverMenu.aspx" runat="server">Item2</asp:HyperLink>
</asp:Panel>