Back to the Future Part II (November 22nd, 1989)
Next to Indiana Jones and the Last Crusade, this was probably the most anticipated sequel of the 1980's - at least for me it was - and it was well worth the wait.
Back to the Future was probably the first movie to ever have a "To Be Continued" at the end - but it wasn't until many years later that I realized the "To Be Continued" wasn't in the original ending.
Another thing that stuck with me was the fact that they included a trailer for part 3 with actual footage at the end of the movie. I don't think that had ever been done either and I haven't seen it done since.
I was nine and I totally bought in to the whole hover board thing. It seemed plausible and I wanted one so badly - let's face it, I still do. And according to the movie I only have six more years before I can have one - or perhaps a flying car, or shoes with power laces, or maybe some totally rad spandex future clothes - ah, the future.
(Image from impawards.com)