I am not maintaining the events calendar anymore. Here are some links to other pages that you may find useful instead:
 

Track Day Calendars:

• Pukka Driving Events Calendar
• track-days.org

Clubs and Organizations:

• Team Miata: Miata Performance Driving School
• Miata Performance Club Events
• NASA
• Green Flag Driving Association
• OpenTrack
• Porsche Owners Club
• Speedtrial
• Touring Car Club
• Thunderhill High Performance Driving School
• TracQuest
• Golden Gate Lotus Club
• Team Racing (Miata Events)
• NCRC