I'll start off with the opening crawls. I've used the overlayed version for this, to make the inconsistencies between them clearer.
Funny thing is, there's a different amount of blank time at the beginning of each DVD, so they were all completely out of sync with each other. I decided I'd leave that alone for the movie overall - there'd be no room for crazy conspiracy theories if I had to move them to get stuff to match up - but just for this one clip to show the differences between the crawls, I trimmed 81 frames from the beginning of AOTC, 49 frames from ROTS, 25 frames from ANH, 25 frames from ESB, and 26 frames from ROTJ, so the first frame of the Star Wars logo in each movie coincides. Weird how the OT is much more consistent about that than the PT.
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ANH, ESB, ROTJ, and ROTS all start with a Star Destroyer in space, and the first shots of ANH and ROTJ are almost exactly the same. That's obvious, and obviously intentional.
R2-D2 is introduced in the first scene in AOTC, ROTS, and ANH. Not all that interesting really, but he's my favorite character. Bear with me and scroll down.
Okay, holy crap. This is awesome. I think it justifies the whole thing, and I'm only four minutes into it. The first appearance of Palpatine in TPM and AOTC is ON THE SAME FRAME. And at the same time in ROTJ, Vader is telling Moff Jerjerrod that the Emperor is coming.
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Anakin standing next to Obi-Wan in AOTC and ROTS, and in ANH as Vader standing next to... that other guy.
And the holograms of Palpatine in TPM and Luke in ROTJ in these scenes appear at about the same time.
Jedi Rocks goes very well with the Anakin/Obi-Wan vs. Dooku fight. Fun.
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Obi-Wan jumps out the window just about at the same time that Anakin cuts Dooku's head off.
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The power couplings in AOTC do whatever the hell it is they're doing about a second after the ray shields go up in ROTS.
Wookiee hugs in ESB and ROTJ.
If anybody's curious: that's how much was done when everybody started linking to me. Anything after this was added later.