This was our first time to San Francisco and I had a great time. The place was beautiful and full of life. We decided to go on one of those tours (http://www.judysbook.com/members/Jolene/posts/2006/11/485793/) Anyway we did a quick stop at this museum. I thought it was pretty cool and all but the best part was when the cable broke and the cars all stopped. We had to take many detours until the cars were back up and running.
They had two cable cars inside that you could see up close and all but could not get on them. The little store inside was neat and showed some history.
I recommend stopping in there for a little peak. Won't take you long to look at.