'Raiders of the Lost Ark' cameo

[snopes]

Comment: Did R2-D2 and C-3PO make a cameo in Raiders of the Lost Ark?

[Stoneage Dinosaur]

Apparently they are carved on the wall of the Well of Souls.

[Arriah]

Yes, the airplane that Indiana fought around was actually R2D2 and they used C-3PO for Hitler since he had been dead for many years at the time of filming.

ETA: Hmmm. Maybe not such a silly question after all.

[forcadragons]

Another Star Wars in joke in the Indiana Jones series is that the club in the opening of "Temple Of Doom" is named "Club Obi-Wan".

[Mycroft]

They also appear to have used the same sound effect for DC3-runs-out-of-fuel in Temple of Doom as Millennium Falcon-breaks-down in Empire strikes Back

[Tootsie Plunkette]

A small model of R2-D2 was included on the mother ship in Close Encounters of the Third Kind. You can actually see him (upside-down) as the ship comes over Devil's Tower.