Sometimes I am amazed of all the curious things you can find on the internet, because I didn't know that there was a site where you could find all the writing systems and languages in the world, fiction or not! Once I entered to Omniglot, I couldn't resist to search for some of the typical science fiction movies and series to find their alphabet, here are some of them...
The Ancients alphabet (Stargate)
The Ancients alphabet is the written language of the Ancients (Anquietas), a race of highly advanced 'ancient' Humans who evolved in this galaxy millions of years ago. The original version of the Ancients font was first seen in the SG-1 episode "Torment of Tantalus".
The Dancing Men (Sherlock Holmes)
The Dancing Men script is a secret alphabet used by a gang of American criminals in the Sherlock Holmes short story "The Adventure of the Dancing Men", which appears in The Return of Sherlock Holmes, A Collection of Holmes Adventures by Sir Arthur Conan Doyle.
Klingon (Star Trek)
Klingon is the language spoken by Klingons, alien characters in the Star Trek films and TV series.
Kryptonian or Kryptonese is language or the fictional planet Krypton, birthplace of Superman.