This year's timetable has yet to be published. Here's last year's:

http://www.suzukacircuit.jp/en/f1/timeschedule.html

If you are in the Nagoya area and have any interest in architecture (particularly in regards to the transition period when Japan began to adopt Western building styles) I would urge you to consider Meiji Mura in Inuyama. Inuyama also has a small but wonderful castle, I believe it is the last to remain in private hands.