An event can be a variety of different things including a party, sporting event, or even something specific such as “The President’s Birthday.”
Or if you are interested check out this example which comes straight from Google’s documentation:
Or this example from schema.org
A search engine crawler will read the code. After a period of time, the search engine results page for users performing a “branded search” will yield the below information (see photo). It is important that this information generally presents only for users who are performing the search within your geographical area.