Mario Kart Wii Tournaments, which will be coming every few weeks. The first one, available now, is a competition for fastest time on Mario Circuit. "Look closely though," said the press release, "something may be different." (For whatever reason, we haven't been able to get online to see what difference there might be.)
Best times will be recorded and viewed on worldwide rankings. Future tournaments might also include collecting coins and Wii Wheel-specific challenges.