inserting date created with new record

I'm trying to set the date created when I add a new record: (using a
FormView)

This works:
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString
%>"
InsertCommand="INSERT INTO [AdultEvent] ([DateCreated],
[DateLastModified], [EventName])
VALUES ('04/23/2008', '04/23/2008', [at] EventName)"

but I want the dates to be the current date and time.

I've tried variations on this:
VALUES ('<%$ DateTime.Now.ToString('MM/dd/yyyy') %>', '04/23/2008',
[at] EventName)"

But I get:
System.Data.SqlClient.SqlException: Incorrect syntax near 'MM'.

Or:
VALUES ('<%$ DateTime.Now %>', '04/23/2008', [at] EventName)"

System.Data.SqlClient.SqlException: Conversion failed when converting
datetime from character string