Overnight layover in Zurich

Coincidentally, we were bumped to Warsaw when flying from Zurich to Copenhagen this summer.  Took the bus into the city, walked around a bit, took a few photos, had a cup of coffee, and took the bus back to the airport.  Totally enjoyable four hours.
The train is easy and inexpensive to go between the airport and the city (15-20 mins & about 6 CHF / USD).  Re: Zurich hotels, not really sure but there's a great hostel in the center of the city that would probably be one of your least expensive options but it's usually booked, so you'd have to arrange it ahead of time.  There's also a women's hotel in the Seefeld area that might be good for you.  I can send you the info for one or both if you like.  You could walk around and take pix at night, but you are probably leaving too early the next morning to do much other than get a cup of coffee or walk along the lake before you would likely have to head back to the airport to make your flight.  You can use the Hauptbahnhof / Main Train Station or the Stadelhofen Station (closer to the lake) for either your in or out journey.
Let me know if I can help with more info.