The web site is in German but here is my rough and ready take on it..
Basically tonight the museums open and it is possible to visit them after dark each place has something difference , quiz, music and food.
I think there is a bus route running between the various locations as well

http://www.langenacht.ch/programm/kalender.asp

enjoy

Are the museums too crowded tonite? Is it a good bet to visit tonight rather than any other day?

The atmosphere is really different some are more crowded than others but none are packed.

Just came back from the Landesmuseum. There were quite a few visitors (maybe also because it was the last evening of Rundfunk.fm).

I had figured I wouldn't be awake enough to make it to this night having just gotten off a plane from the US this morning. And here I am, still up at 3:30am reading this and thinking that for once there _is_ something open in Zurich when I'm awake. Oh well.

Maybe next year.

I like Lange Nacht, but didn't stay out too late. I found something more interesting to do. I only caught one exhibit - Michel Comte. Nice body of work.

Anyone see anything particularly interesting?