Star Wars;
On the Jawa's
transporter, when R2 looks around
in one of the shots, you can very
clearly see the person who is inside
R2 through his little eye hole.

Raiders of The Lost Ark;
After
Marion supposedly dies in the truck
explosion and Indy is drinking
outside at the bar, watch to the left
of him. You can see a man wearing a
modern t-shirt and jeans walking
through the crowd.