ThePHPCMS does not currently support 'date ranges' on pages.

What we usually recommend is the following steps:

1. Create one section called Events and have it show pages before and including the page date
2. Create another section called Past Events and have it show pages AFTER and including the page date
3. When creating new event pages, put the page in BOTH sections
4. This will cause the page to 'automatically' move from the Events to the Past Events section on the appropriate date.

While we also recommend leaving pages on your site as good keyword 'bait', you can always go in later and delete any that you no longer want in your 'archives'.