Something like this should work
<%# System.DateTime.Now.Subtract(Convert.ToDateTime(Eval("Date"))).Minutes + " minutes ago" %>
Else have a public function, say,
public string GetInfo(object date)
{
return DateTime.Now.Subtract(Convert.ToDateTime(date.ToString())).Minutes + " minutes ago";
}
and then use it as
<%# GetInfo(Eval("Date")) %>
Hope this helps!