Once upon a time Windows SDK (or it was Visual Studio) had a tool named IROTVIEW which enumerated the Running Object Table (ROT).
Where can I get this tool now?
This site has a pretty good viewer for download in 32 bit and 64 bit versions.
This site has a simple enumeration class, but it needs some improvement since if you have two objects running with the same name (like two instances of Excel), it cannot populate the dictionary with the duplicate key.