Beyond the big organizational frameworks (AI Councils, Centers of Excellence, etc…), what's one AI strategy you've championed that delivered significant, measurable impact to your business?

Very similar to the other comments. AI Steering Team (Exec level), AI Communities of Practice (Staff level), Connecting AI to existing business processes (org level), and very active pilot projects. I really enjoyed the last approach. We scanned email for staff using AI who had not followed policy, contacted them, and invited them to take part in official pilot programs with guidance and legal advice. Every person participating had to submit use cases and agree to answering a brief but frequent questionnaire that asked questions about benefits, bias and ethics.

We adopted a two-tired approach. At the user level (essentially MS Copilot) we created a community of practice, co-sponsored by the CIO and another VP from the business, and we supervised/mentored the users, with training resources and exchange of best practices. Finally, we tracked usage so that active users keep their licence and generate demand for AI with their peers (we did not have licences for all).
At the business unit level, we went with a proof of value approach on prioritized use cases (ROI vs feasibility) before deploying in prod.

Pushing people to just do it. Experiment and learn within a framework of security, privacy and governance. But experiment and learn are the keywords.

Consider appointing a senior executive, reporting directly to top leadership, to lead and manage a strategic, organization-wide AI program.