Words for describing an events start time

I am trying to classify events into two distinct groups. Event, in this context, means a public event which people might go to. This includes a broad collection of things including concerts, plays, maybe even a book signing, or community gathering.

The differentiating property is whether people are expected to show up at the beginning of the event or if they can show up at any point throughout the duration of the event.

Examples of events you should be punctual to: Concerts, plays, classes, presentations/talks.

Examples of events you could show at any time: Special museum exhibits, State fairs.

I'm looking for words to describe both categories.

Here is a list of some words that come close but don't quite meet the bill:

For events which you should be punctual to:

• concrete: well defined given a context of time but not by itself

For events which you can show at any point:

• ongoing: includes the connotation that it is presently happening right now|
• 'All Day': This fits the meaning that you can go at any point during the day, but ascribes the additional idea that the event is throughout the entire day.

Thanks for the help!

Solution 1:

You use the word "punctual" to describe how you should arrive, so perhaps the word could be extended to describe the event itself. A concert or play is a "punctual event", while a fair or gala could be a "flexible event".

Solution 2:

I would use these terms:

on time event: This concert is an on time event. Patrons arriving late will be allowed to take their seats during intermission.

anytime event: The after party is an anytime event. Guests are free to come and go as they please during the party.