I'm currently in the process of reviewing and understanding a bunch of legacy VB 6.0 code. One of the trickiest parts of reviewing such things is getting the “gist” of what's going on on a specific method, or understanding the time-line of method calls in a specific business process.
I discovered a small tool (not free) called Visustin that allows you to paste in code from VB,C#,VB.Net,Java,C++,COBOL,Pascal and Delphi, and it will display a visual call graph of what's going on. It's very cool and it really helps in understating some of those long-running, hard to decipher methods...
The tool is not free, and the installer is that good ol' vb installer program from vb 6.0, but the demo version hold enough functionality to let me use it as is. It just doesn't allow you to print or save the graph once it's created, which is cool for me, as I use it mainly as a quick ad-hoc “How does this method work” kind of queries. Coolness achieved. I wonder if there are more tools like this.