It really depends what kind of stuff you are into but I'd recommend checking out the Computer History Museum. There is a lot of awesome historical stuff there, and it is free. It might be quite boring if you're not into computers though.
Oo, I finally will get to see a punchcard computer in person! Very cool, thanks! Reminds me of the time I accidently found a Thomas Edison exhibit in Bandai Museum outside Tokyo.
It might be a good time to see it because I think a replica of the difference engine is on display there... pretty cool: