How do I insert more complex server-side script into an aspx page

Hi, I've got a question I've been playing with, but I can't seem to get it to work, nor find any decent documention online.

I am aware of the ability to insert server-side script into the aspx code - for example, in a gridview
<ItemTemplate>
<asp:Label ID="lblItmUOM" runat="server" Text='<%# Bind("smp_uom") %>'></asp:Label>
</ItemTemplate>

 

but how can you inject more sophisticated code.  I am trying a simple example for creating the local date string.  I can execute the following fine: <%@ Page Language=" ...