The Back to the Future movies are classics. With Marty McFly and Dr. Emmett Brown as the characters we remember, there was also the Flux Capacitor that made it all happen.
If you recall, Dr. Brown claimed that the vision of the Flux Capacitor came to him after he has hit his head. Since then, his research has changed, and he was able to create the wonderful time machine (in a DeLorean of all vehicles).
For the major fans, or those who want to attempt to go back (or forward) in time, you can purchase your own Flux Capacitor for $230.
They do mention that they are not responsible if any time oriented problems occur, or if you are stopped for going 88mph as needed to go back in time.