Create an Event.
When you add the tickets, select Add Free Ticket.
You can still limit the total attendance and the number of tickets that can be "purchased" per order or per contact, as well as making the event open to everyone or only Members for each Ticket type.
As with all Ticket types (free or costed) you can set a Description, Sale Start/End date (if required), Ticket Limit per Order and, if required, Require Membership.
Note: You can collect information about each Ticket holder (if required) using the Collect Attendee Information > Per Ticket