These 3 points will help you to understand calendar better.
1. Calendar views are sticky.
This means that if you your last calendar view will remain until you change it for a new one. Let's say you selected the below view, you leave your calendar and go to a different place in Marketo, when you come back to your calendar you will find the same view that you had before.
In the example below you can see that you have Email Programs, Main Events, Email Program Tests and Webinars as entry types and APAC and Default as Workspaces.
If you leave your Calendar, go to Marketing Activities and then you come back to Calendar you will find the same view that you had before.
2. Save views as filters
You can save a view that you use frequently.
Go to filters / Type in Custom
A new box will appear, enter a name for a view.
I entered 'View for community'
You can share a view with someone who has a login access to Marketo.
Click on the share symbol as indicated below.
You will be provided with a link.
Share this link and as long as the other person can login, they would be able to see the same view.