Creating a new buttons or links to simulate the same action as switching views by the Ribbon, can be very easy to use while the Ribbon is hidden, anonymous mode, or just new UI request.
In order to do that, add this onclick function to the <a> tags or to any other tags (image, input and more) on top of the web part zone above the Calendar web part:
For Day view - onclick="javascript:MoveView('day');"
For Week view - onclick="javascript:MoveView('week');"
For Month view - onclick="javascript:MoveView('month');"
