It's easy to make your calendar public, meaning anyone can view it without having to have a KeepandShare account or be on a share list.

Just follow these steps:

1. Log into your account and click on the calendar tab
2. click 'Customize' on the blue bar
3. In the Share With controls, set one of the groups to be 'Public'
4. Click 'Update'

Here is an image of the Share With control being set to 'Public':

Granting edit rights: if you check the edit box, then visitors to your calendar will be able to edit it the calendar. Note that if you share the calendar publicly and with edit rights, then anyone can edit the calendar even without having a KeepandShare account. This is probably not appropriate for most personal calendars but can be an easy way to allow sign ups for office hours and other schedules without requiring that people have a KeepandShare account just to view and edit your public calendar.

(search terms: publicly visible calendar; public calendar; no log in; no membership required)