Are there any good websites that offer free online movies?

I don’t have cable and I recently cancelled my Netflix account because I went back to school. I don’t watch tv much, however sometimes I do get a little bored if I have to stay at home. Does anyone know of any good websites where I can watch movies online for free or any tv shows that might be intersting over the web? I don’t want to worry about viruses though nor do I want to have to download some crazy programs that might harm my computer in the long run.