WhatsOpen is a quick utility that came out of an MMUG meeting. Someone posed a question regarding how to tell what application has a volume open so they could quit out of it and eject the removable media.

It is a somewhat common error that a file on a removable device is held open by one thing or another and the system will not eject it. This program lists all open files on your system, with an option to filter them, and then allows you to kill the application that has a selected file open. Pretty straight forward but something that a lot of people seemed interested in at the meeting so I whipped one up quickly.