http://www.imdb.com/title/tt0078869/ - The Black Hole - I've seen this movie twice on TV and every time I cringe, one of the worst mind-numbing sci-fi movies, on the other hand, the maintenance robots are funny (and occasionally parodied online).
http://www.imdb.com/title/tt0087451/ - Ice Pirates - This movie is funny in places but overall it's pretty bad, so classic, but fails to be good, I wouldn't say it's one of the worst though, just bad.
http://www.imdb.com/title/tt0312528/ - The Cat In The hat - horrifying, just horrifying (and yes I am a Dr Seuss fan, and no, I couldn't stand to watch more than 5 minutes of this)
http://www.imdb.com/title/tt0082340/ - Escape from New York - bad.
http://www.imdb.com/title/tt0116225/ - Escape from L.A. - legendarily stupid, poor.
http://www.imdb.com/title/tt0114898/ - Waterworld - legendarily bad.
http://www.imdb.com/title/tt0477348/ - No Country For Old Men - This movie baffles me in how it gets high reviews, I hated it, violent without any point, I couldn't find any lasting value in the experience.
http://www.imdb.com/title/tt0213327/ - Andromeda (series) - first season great, second season good, all the rest bad.
http://www.imdb.com/title/tt0103521/ - Red Dwarf USA - I can't even imagine how bad this is, and hope I never see it.
On the other hand here are some series I like (GOOD, NOT BAD):
http://www.imdb.com/title/tt0250750/ - Starhunter (2001) series - I loved this series, the production values are rock bottom but the stories are interesting and far more original than most sci-fi series.
http://www.imdb.com/title/tt0340491/ - Starhunter (2003) series - This gained production values and lost almost all originality, but still managed to be better than later seasons of Andromeda.
http://www.imdb.com/title/tt0094535/ - Red Dwarf (1988) series - Awesome, continually stupid but awesome.
All hail cult-classic british sci-fi shows!