Here are some full length science fiction classics you can watch on YouTube.
Logans Run
http://www.youtube.com/watch?v=c-fV6-XEk-Y The Time Machine
http://www.youtube.com/watch?v=rcziOmxNuus Robinson Crusoe on Mars
http://www.youtube.com/watch?v=urccN0eKk3Y The Forbidden Planet (starring Leslie Nielsen, look how young he was!)
http://www.youtube.com/watch?v=R8aIl03DTzg The Blob (with Steve McQueen)
http://www.youtube.com/watch?v=NbgMbVWAB7wI've been watching the Logan's Run TV series, and the episodes have been great, very imaginative and contain deep themes about our society. I'd recommend you all check them out. All 14 episodes of the series are on YouTube. Here is episode one:
http://www.youtube.com/watch?v=cCkRVEehkUc The "domed city" in the series reflects what our society is turning into, in many ways.
Here is another interesting film called "Return to Oz", the sequel to "The Wizard of Oz". It's almost forgotten by now, by every review of it I've read was very positive and said it was a wonderful film. If you want to see it, here is the whole movie on YouTube:
http://www.youtube.com/watch?v=2MSjHzV-5SE I haven't seen it yet, but I will soon.