It's finally here! The day 'Back To The Future' fans have been waiting for since 1985: October 21, 2015! Now if you are a BTTF novice, you may not remember that that's the day Marty and Doc travel to in "Back to the Future 2."

Fans all over the world are planning special events for the day including watching all three films back-to-back, and we've created the ultimate drinking game if you're having your marathon at home! If you're 21 and want to add some more fun to your BTTF marathon, make sure you have this guide handy.

So grab your Hoverboard, self-lacing Nikes, and Mr. Fusion sit back, relax and get ready to be very VERY buzzed while watching Marty McFly try not to mess with the future... too much! Happy Oct. 21!