Sci-Fi is the best. A good Sci-Fi TV show is the bestest. We warn you, you need to be sure that you have plenty of time and nothing to do before watching these shows listed below. They are addictive and might turn you into a "no-lifer." And you know what, we are totally okay with turning into one, unless we have more episodes of Battlestar: Galactica.
Plot summaries are from IMDB unless cited. Shows are listed randomly.