You may sometimes want to create an event that you don't want to publish or accept registrations for via the portal. However, the system process that sets up what you see on the Registration wizard in CRM and the Portal are the same so in order to have an event show up in your wizard you must have Publish to Portal set to yes. So how do you hide it from people on the portal?
On the Meeting Record make sure Publish to Portal is Set to Yes. And make sure the begin and end date is in the future.
On Registration Fee make sure Hide on Portal is to No. And make sure the Begin and End Date is in the future.
Set the Meeting as Invitation Only

Click View Query and set a criteria that no one fits, otherwise known as an impossible query.

Examples could be Contact equals the staff member setting up the meeting (you would be the only one to see it)
Contact NRDS ID equals abc12345 or something equally impossible.
This will keep the event from being viewable on the portal by anyone else since no one fits the query, but as staff you can override this and register anyone you want in the meeting registration wizard.
When else could I use this strategy?
If you have a meeting in the past and need to add registrations, you can use the steps above to reset the meeting so that you can enter those registrations without having the meeting be reopened with new dates on the portal. When you are done registering the people you need to you can reset the dates and the display if you choose.