I have an excel macro that detects the current spreadsheet being closed and runs: Private Sub App_WorkbookBeforeClose(ByVal Wb As Workbook, Cancel As Boolean) MsgBox "App_WorkbookBeforeClose: " & Wb.Name End Sub Now I suck with VB, but before I bang my head against a wall trying to figure this out, Is there a way of having App_WorkbookBeforeClose run another executable? Is this possible?

Search in MSDN Library or in the internet for the Shell function.
The shell function must be available from VBA.
This function spawns a process by passing a path to an exe file.
This function spawns a process, but unlike CreateProcess, it don't take ownership of the process, so when excel is closed the spawned process remains alive.

Using ShellExecute instead of VBA's Shell function