I just finished reading Dino Esposito's excellent article from the September Msdn Magazine titled: Design Smarter Tracing for ASP.NET Pages
http://msdn.microsoft.com/msdnmag/issues/04/09/CuttingEdge/default.aspx
In it he shows how to monkey around with the Response stream via Response Output Filters. The demo is a useful and practical insight into this black art by way of a demo which makes the tracing output which is appended to the bottom of your pages more useable.
Highly recommended!