I'm watching back to the future 2 on abc family channel and I keep seeing commercials for a new movie "Project Almanac" coming out Jan 30th. The kids have a time machine and the one kid says "first rule: don't change anything!"
Seems to be the same concept as BTTF in a way but I guess all time travel films go by the same idea of changing things in the past and how they affect the future.
Looks pretty cool though ...