IIS Debug Toolkit: IIS Crash/Hang Agent & IIS Dump (Version 1.1)

Two tools make up the IIS Debug toolkit and are
designed to help figure out what requests were in flight when IIS
terminates unexpectedly or take action when a request hangs. Use
this tool if you notice IIS terminating unexpectedly or if you want
to figure out why a request is hanging.

Microsoft Download Center

Useful IIS troubleshooting tools.