October 21, 2015 is the day in Back to the Future II where Marty McFly and Doc Brown travel in their Delorean time machine, and to celebrate the date Siri is offering up some well timed responses. Today Siri is happy to share her thoughts on the Cubs winning the world series, hover cars, computers, and more. Just tell her "Happy back to the future day" to get a response. And a side note: after today all of Back to the Future will have taken place in the past. Happy Back to the Future Day!