Google Calendar
Below is a test/sample Google calendar (paldomdemotest) that we created showing miscellaneous events, color options, etc. It has US Holidays incorporated in it. The top area of the calendar can be a custom color and the events can be color coded. Events can have a lot of detail and attachements added. It is embedded as an iframe in a custom html block. It is displayed as a month view and also as an agenda view (list) which is good to put in a sidebar or column on a web page.
Below is a sample of the above Google calendar displayed as a list inside a section block with a variable width. This view only shows dates that have events posted.
Below are Google calendars for two of our clients that they maintain and it updates automatically on their website. It is inserted using an iframe in a custom html block.