Men in Black 3
The high point of my relationship with Men in Black 3 came the first time I saw the trailer, and witnessed for myself the majesty of Josh Brolin playing a young K, the character originated by Tommy Lee Jones. Because, come on, that is killer casting, and (from what I saw in the trailer) Brolin nailed the impression. But then I never saw the movie, and the Brolin/Jones MIB3 casting was pretty much forgotten after the Gordon-Levitt/Willis young/old casting showcased in Looper a few months later.
But even if you, like me, missed MIB3 when it was in theaters, it might be worth catching on home video for its importance as a cultural artifact. You can scrutinize Will Smith's performance to see whether it's changed now that he's (allegedly) a Scientologist. You can make it a two-screen experience, looking up photos of Smith's infamous megatrailer while you determine whether Smith's offscreen comfort improved the film. But if the meta stuff doesn't do it for you, there are probably aliens.