How do you fill in the time between End of Grade testing finishing and the end of the school year?

This is something I struggle with each school year. The students that have scored at/above proficiency do not participate in the remediation activities, so something has to be created to fill in the gap of 5-7 days, depending on when testing ends. I don't like giving them "busy work", but the expectation is for them to be working. Add in the fact that they always seem to know that final grades have been submitted, so the "Is this for a grade?" discussion doesn't come into play. Since "testing season" is not too far away, I want to be able to share some ideas for planning.