Unfortunately, this blooper can only be seen in the theater, unless, that is, you have a letterbox version. In the Ewok camp where Luke and everyone are tied up, you can see Chewie stick his head from the left side of the screen behind one of the Ewok huts. Remember, he's supposed to be tied up at this point! Also, there's a shot of R2 untied when he hasn't been cut loose yet (I'm not exactly sure where this is).
TWO mechanical hands?
When Luke is on the speederbike on Endor, right before Luke's vehicle hits the tree, you can clearly see that in three different shots Luke's glove (masking his mechanical hand) is on different hands. In the first cut his glove is on his right hand, next shot, his left, and back to his right again.
Powerful Force
When the Emperor is leaving the Imperial Shuttle Craft, on board the Death Star, while walking down the ramp, his head somehow manages to go through the front of the Shuttle Craft, unscathed.
Lando must be fidgeting
When Han and Lando are talking in the rebel hanger right before the strike team departs in the stolen Imperial shuttle, you can see that Lando's gun belt strap across his chest changes sides between different cuts during the same scene.
Endor or California?
Right after the Rebels have exited the shuttle Tyderium in ROTJ, you can see a wooden fence in the background. The scene was actually filmed in a redwood forest, so this explains the mistake.
Double sabers
In the scene after Luke and Vader have fought, and Luke is hiding, while Vader is taunting Luke, Darth his holding Luke's lightsaber in his left hand!
Greedo was wearing a bulletproof vest
When the droids first enter Jabba's throne room, you hear a lot of alien voices murmuring... if you listen closely, one of them is Greedo's voice speaking the EXACT same dialogue he said to Han in ANH.
Ewokese isn't that weird after all
On Endor, just after C-3PO sits up and the Ewoks start to praise him, the camera pans to two Ewoks talking. If you listen carefully, you can hear one of the Ewoks saying, 'That guy's wise," and then the one next to him says, "More than I am short."
