UBB.threads PHP Forum Software Community Forums UBB.classic UBB.classic 6 Support custom introduction page

No, something would have to be written.

Have you thought about using the Forum Intro? (CP > General > Forum Summary Options > Forum Introduction) Or maybe the Board Rules, with the Force Registered Users to Agree to Changed Rules checked? That would require users to view that page whenever they login IF there are changes. (CP > Registration Settings)