7. George Lucas appeared with a cameo in Episode III – Revenge of the Sith as Baron Papanoida. Another instance was when Lucas developed a cough during the filming which he recorded and used as General Grievous’ cough.
8. In Episode V – The Empire Strikes Back, the deep chasm in Bespin where Luke and Vader have their epic duel was actually a matte painting, and so were many scenes including the scene in which Luke and Leia blast Stormtroopers across an inactive bridge.
9. It is said that Peter Mayhew, the actor who played Chewbacca, had to be accompanied by crew members wearing bright colored vests while filming in Californian forests so that he won’t be mistaken for Bigfoot and shot.
According to Haden Blackman, who worked at LucasArts and was the writer of many non-cannon comics of Star Wars, this happened during the filming of the scenes of Endor in Star Wars: Episode VI – Revenge of the Sith. Later, he wrote a comic named Into the Great Unknown about Han Solo and Chewbacca landing on Earth. (1, 2)
10. In an interview, Ian McCaig stated that George Lucas asked him to create Darth Maul from his worst nightmare. However, it was too much for Lucas who shuddered when he looked at the drawing by McCaig and asked him to give his second worst nightmare.
Ian McCaig, the character designer for Darth Maul, Queen Amidala, and many others, used his own face and added red skin and black marks to make the Sith Lord look formidable. (source)
11. Mark Hamill was bitten by a snake while filming Episode V – The Empire Strikes Back. It was in the scene where Yoda and Obi-Wan Kenobi tell him to finish training in Dagobah. However, the snake was harmless.
12. While visiting Steven Spielberg on the sets of Close Encounters of Third Kind, Lucas thought that it would be a bigger hit than his Star Wars. However, Spielberg disagreed with Lucas. Then, Lucas proposed they trade 2.5% of profits from each other’s films, and guess what, Spielberg still receives the profits.
Lucas and Spielberg have been friends for a long time. Spielberg even gave many suggestions including hiring John Williams, the movie’s music composer, that proved to be a good decision as he composed many iconic music sequences. (source)