With over 19 million units of worldwide sales, there was no way Sega would pass up on developing another Mario & Sonic at the Olympic Games title. Mario & Sonic at the 2012 London Olympic Games is indeed in development for Wii and the Nintendo 3DS.
The announcement in Japan notes the Wii version will sport some new events like horseback riding and soccer. That might be a bit unfair for Team Sonic since Mario and his friends have been practicing in the Mario Strikers series. Track & field, swimming, and table tennis events have been revised. Dream matches, which break Olympic rules have been completely changed for Mario & Sonic at the London 2012 Olympic Games. Both versions have cooperative and competitive multiplayer modes.
Just like past Mario & Sonic Olympic series titles, Sega will publish the game in Europe and North America. Nintendo will handle the title in Japan. Rivalries will be settled… on horseback.