When we went for a long MLK weekend in 2008, I was disappointed to find out Spaceship Earth (one of my favorites) was not going to be open. I think it was scheduled to open maybe Mid-February (although I do not have the best memory).
Anyway, was pleased to find that they were doing a soft opening (or whatever they call it) and we rode it twice. There was a big sign with kind of a disclaimer that they were just testing it, could close it down anytime, etc.
And both times we went on it we got stuck for a bit! But I didn't care, was just happy to ride it!