Sci-Fi is a fiction genre based on imaginary concepts which are based on scientific facts and postulates and work somewhat withing the laws of nature. It is very different from fantasy in that sci-fi fiction does not depend on magic, spirits, or unexplained phenomenon. Usually the sci-fi fiction plots are based in a future time line or a distant historical past. Some plots are based on space travel and interaction with living beings or machines from another planet or galaxy. They also depict the use of some advanced gadgets and machines that do not exist yet. Such gadgets have been a source of inspiration from a lot of real life inventions like the cell phone, PDAs, MRI machine etc. We still need to wait for the teleportation device though. The Sci-Fi fiction genre as been adapted by the movie, video games, and comics industry with great success and there are millions of sci-fi fans all over the world. This genre is especially popular among the teens and youth. There are several sci-fi conventions organized by sci-fi non-profit organizations run by volunteers to cater to he interests and enthusiasm of fan groups around the world. Recently a lot of fan groups are producing non-commercial fiction based on established films, books, TV shows or comics. It has been great source of Halloween costumes for the fans. All most all Sci-Fi costumes are based on TV shows and movies that are popular among the fans like Star Trek, Star Wars, Starggate (a military science fiction franchise), Iron Man, X-Men, GhostBusters, Resident Evil, Warcraft, Predators, Superman, A.I. Artificial Intelligence, Atlantis: The Lost Empire, Transforms, Alien, and endless other movies and shows.