Debugger Canvas is an excellent debugging tool which will be introduced into Visual Studio by early next month. From Offical description – Debugger Canvas pulls together the code you’re exploring onto a single pan-and-zoom display. As you hit breakpoints or step into code, Debugger Canvas shows just the methods that you’re debugging, with call lines and local variables, to help you see the bigger picture. It will require Visual Studio 2010 Ultimate SP1 (or the trial version).

You can get more information about Debugger Canvas from here and here also.

Here is a demo video about Debugger canvas.