Adding an events calendar to a Drupal instance is pretty easy thanks to Kjartan Mannes who authored the Event module and Gerhard Killesreiter who maintains it.

I was asked if I would add a Calendar to the Nonprofit Commons site--dedicated to nonprofits in Second Life--to aid in booking space across the two sims. We often have events, and sometimes they can conflict with one another.

The steps are easy. In this instance, I'm adding the module to a Drupal 5.x install.

1. Go to http://drupal.org/project/event and download the module
2. I use Cyberduck, but use your favourite FTP client to move the package to /sites/all/modules/ and expand the package.
3. Enable the module at /admin/build/modules
4. You will find that there are four elements that you can make use of--Basic event, Event, Event All Day, and Event Views. In this instance, I enabled all of them.
5. Next, add access to the roles you want to allow to make use of the calendar at /admin/user/roles
6. If you leave things as they are, posts from the calendar will automatically promote to the front page. I didn't want this to happen, so I popped over to /admin/content/types/event and unchecked the "Promoted to front page" option.
7. Finally, you can add events by going to "Create Content" /node/add.

That's it. It is an easy and quick way to add calendar functionality to your site.