Create an event without a date - Register Interest

It would be good to have a way of creating an event without a date on it, but that can still be shown in EB Category Layout. We have events which are only run when enough interest is shown, so a way of listing these events with a "register my interest" link on it, that would send admin an email with those details. Then if enough interest is shown we can turn it into an actual event.
Thanks in hope