Spike TV's "SCREAM 2010" awards will celebrate the 25th anniversary of Back to the Future with Michael J. Fox, Lea Thompson and Elisabeth Shue reuniting onstage. To advertise the awards they got Michael J. Fox to remake the original teaser for the time traveling classic:
Original Teaser
Also here's a look and the 'Back to the Future' that might have been with Eric Stoltz as Marty McFly:
UPDATE: Michael J. Fox and Lea Thompson Reunited
Michael J. Fox and Christopher Lloyd at the 2010 Scream Awards: