Hi!
This should definitely be possible.
The first resource you should check out is our Themer’s Guide which covers the basics of safely customizing and overriding templates.
The fine detail of something like this really hinges on the structure of your theme, but in principle since you are using the Default Events Template you could override that very template (default-template.php) and simply add a get_sidebar() call.
I’d love to be more specific, but since different themes work in different ways it’s really something where a working knowledge of the theme itself will come into its own.