Sometimes it is useful to copy over a site collection (SPSite) from a WebApplication to another. This can be easily accomplished in just a few lines of code:

 static void Main(string[] args)
        {
            String url1 = "http://web1/sitecollection1";
            String url2 = "http://web2/sitecollection2";

            SPWebApplication webApp1 = SPWebApplication.Lookup(new Uri(url1));
            SPWebApplication webApp2 = SPWebApplication.Lookup(new Uri(url2));

            webApp1.Sites.Backup(url1, "c:\temp\site.backup", true);            
            webApp2.Sites.Restore(url2, "c:\temp\site.backup", true);            
        }