You could always roll your own with Google Calendar. I have a client who is asking about exactly the same thing. I've been looking at this: http://libtechtalk.wordpress.com/2010/02/16/guest-post-sign-me-up-e...
Doubt I'll go with it as it's not built in enough but if you aren't bothered about that and can do it yourself it should provide what you are after...
It needs this Calendar add-on to work.http://www.concrete5.org/marketplace/addons/calendar/...
A calendar that deeply integrates with concrete5. New pages are automatically made for each event, calendars can be cross referenced and aggrigated, several front end interfaces including Month View, Agenda, 5 Week and List. Features
-Add multiple calendars to your site, and events beneath them.
-Any calendar can display events from all calendars on the site.
-Easily add events in the context of a calendar.
-Calendar display features four modes: standard month view, agenda view (which lists upcoming events and their summaries in a progressively loaded list), next five weeks, and full list.
-Every event is an individual page, which means concrete5 blocks can be attached to it, it can be moved through the dashboard, etc... Aliased events will work under multiple calendars.
-Events can be marked as featured, and a calendar can be set to show only featured events."
Get it here-http://www.concrete5.org/marketplace/addons/calendar/...
Not ideal, but a work around solution may be to-
1-have a calendar ready with events. (page name would be something like 'events' or 'calendar'),
2-create a submission form on same page. (Containing text boxes for users to enter details. e.g- box 1- event, box 2- date, box 3- number of tickets required, etc.
Now, you can at least have a working calendar with events and a way for users to submit their orders.
I hope I'm correct in saying this, but as long as they submit the form on the calendar page, then you'll know its regarding the events/calendar.
Still a noob myself, hope I didn't confuse you. It's the only way I could see of fixing that problem.
Hope it helps,
Good luck with it,