Science fiction and fantasy entertainment are everywhere in pop culture today, thanks to TV and film franchises such as Star Wars, Star Trek and Lord of the Rings and online role-playing games (World of Warcraft, etc.) Yet long before science fiction became big business, fans heavily promoted the genre through word of mouth. Starting in the late 1930s and ’40s, groups of like-minded fans began gathering to celebrate their love for sci-fi. Those scattered early events have morphed into hundreds of conventions now held across the U.S. each year. These cross the sub-genres of sci-fi, fantasy, horror and speculative fiction as fans “cosplay” their favorite characters, meet popular authors, and hang out with others who share similar interests. Here, in no particular order, are a few of the notable science fiction and fantasy conventions held around the United States. We tried to mix in some lesser-known shows as well that fill different niches in the genre.