Let's see, for Raiders, stuff I've noticed in repeated viewings that my family and friends didn't catch:
1. The whole thing with the other officer in the troop car. Up until I brought him up as my first post on this board (or one of my first, anyway) I'd never seen anybody mention noticing a third officer at Tanis (I'm still trying to figure out where he came from, since he doesn't appear until just before the chase begins, already in the car).
2. When the weird noises and light first start coming out of the Ark, the two soldiers who discretely move from the front of the crowd to the back, are the same two who opened it for Belloq. In pan-and-scan versions it looks like they actually have the brains to sneak off, but instead they stupidly linger at the back of the crowd.
3. Gobler the ventriloquist. It's the worst audio-visual blooper in the movie in my opinion, and one that's been hidden from many viewers' eyes for years due to poor Gobler being consistently offscreen in pan-and-scan versions of the movie. I don't claim to be the first to have noticed it, but I was the one who submitted it to Nitpickers.com (along with the one about Gobler's goggles going up and down in different shots in the truck chase).
4. The so-called Tall Captain who tells Belloq he's arranged the altar for him, despite being seen walking with the procession through the canyon, is not present at the actual opening of the Ark (that I can see, anyway).
5. Not including accidental players like the guy who lands on the truck hood early on, the total number of participants in the truck chase (including Indy) is 19:
1 Indiana Jones on horsie
1 Belloq in black Mercedes
1 Toht in black Mercedes
1 Dietrich in black Mercedes
1 Gobler in troop car
1 German officer in troop car
13 German soldiers altogether; 1 to drive black Mercedes, 2 in truck cab, 7 in back (including the Sarge), 1 manning machine gun in troop car, and 2 on motorcycle with sidecar
(I have way too much free time.)
6. And just to make this an even number of stuff, I guess I just pay more attention to Gobler than most (he really has grown on me despite being possibly the least effective bad guy in the movie; only the Cairo Swordsman is more useless), but when the car goes flying off the cliff, despite there being three people in it, only two fall out as it plummets; Gobler is the one who remains seated. Apparently, he remembered his seatbelt.