Just to make sure you are where you think you are, this page is about how to use Drupal to set up an calendar type of event. There is a whole different page explaining the Events→Conditions→Actions which is a toolset that triggers an action to occur under events and conditions as a set of rules.
It should not be surprising at all the Drupal has a rich starting point to set up an event website. This is because Drupal is very community oriented and runs all sorts of events around the globe throughout the year. Since the Drupal community needs its own websites to manage these events, they have built some really great functionality.
One of the most basic interactions you will have with a calendar is to “Book” something; a room, a meeting, an event, etc. Drupal.org provides a review of the main options. Here a combination of two calendar related modules and another that integrates nicely with them is presented.
The Bookable Calendar module is the workhorse component. It is here where you can establish what is bookable (room, course, etc.), who can book it, for how long, how many days/weeks/months into the future, for how many people, etc. One of the better videos on what can be done with the bookable calendar is here.
The Calendar View module is then your choice for the display of your calendar information. And just like Views, you do various set up selections for titles, what is displayed, etc. However, what you are now working with is a template(s) for the views you start working with and that makes the choice options more calendar relevant out of the box.
The Bookable Calendar module can also be combined with the rules type of logic that the Events→Conditions→Actions can provide.
Another option is the Smart Date Calendar Kit. The inception of this was its module development oriented to simply getting Drupals date and time formats to disply in a more natural, common format. But it moved to then add recurring events, full day, and various date/time features; including a calendar display. This is all explained in a video demonstration of the kit. This calendar approach is oriented more to you or your content editors inputting calendar information in contrast to the ‘bookable’ module orientation toward end-user sign up of date/time slots.
If you are familiar with the Drupal Community, you know that it runs events all over the world of various sizes, durations, and content. As you would expect, a deployment of the Smart Date Calendar module has been configured for their own use. You can find the Event Platform module on the Drupal site. The easiest way to see what is available is to watch a video overview demonstration.