Where can I find a site that shows how to make a 3D card?

Question

Specifically, I'd like a site that will let you print out patterns to make an open card look like a building or a stairway.

Answer 1

I think you are looking for pop-up architecture cards, sometimes also called origami architecture.
Here are a few links for you:
http://members.aol.com/kselena/OA/oamainpg.html#GettingStarted
http://webpages.charter.net/gstormer/
http://members.chello.nl/rebran/oaeng.htm