My mom and I went when we were there in March of 05. There was no line, and a CM was trying to get people to go. We figured, why not? I thought it was something only kids would enjoy (I'm 24, mom's 58) but both of us absolutely LOVED it. Very very entertaining and at the time, quite the hidden gem.
The popularity has definitely caught on though and last I heard there were lines across the whole place of people trying to get in!