Last year I had started to create a calendar that would hold all the events and festivals (まつり / matsuri) in Japan – especially Tokyo – I can get ahold of.
Since it has become a custom in my family to spend several weeks several times a year in the Tokyo area this calendar is used and updated frequently.
Of course it is a calendar you can export, import and subscribe to with any iCal / ICS capable device at your disposal. And probably that means any device that has a calendar app or a browser.
You can click this link and subscribe through google calendar: japanese matsuri calendar