- custom compile-time errors
        #error I noticed a runtime bug here.  If you try to run this again, this will certainly fail.
  or
        #warning I should probably fix this soon.


- custom runtime errors:
        using System.Diagnostics;
        Debug.Assert(1==2);
  or
        Debug.Fail("If we get to here, fail always");
     

- for informal debug logging, use one of these:
        Console.WriteLine("var1 = {0}, var2 = {1}", var1, var2);
        MessageBox.Show("hello world");
  or, to only output to the 
        System.Diagnostics.Debug.WriteLine("hello world");


 

  TODO: what's the equivalent of Perl's Data::Dumper::Dump()?  (OTHER than .ToString())




- To update forms from a different thread...  there are many ways, but the only way to use is this:
            http://google.com/search?q=%22Invoke%28%28MethodInvoker%29delegate%22
        (note: the above requires understanding closures first: http://www.thinkingms.com/pensieve/CommentView,guid,9fe42970-09e3-44e2-a4d0-32d63139351a.aspx)