I have used a couple of good extensions for calendar & booking I use
joomdonation.com/components/events-booking.html
It allows you to book on an event so you can restrict numbers if require, there is a waiting list and paypal integration (if payment is required) & email Notifications, you could possibly use it for online membership but I use RsFormPro
www.rsjoomla.com/support/documentation/v...e/21-rsform-pro.html
Which also has Paypal integration.
They are not that expensive and will save you lots of time, as most of the free stuff has far to many limitation and no support.