I like architecture that thinks beyond the ordinary while still trying maintain functionality. Here are some interesting stairs designed by TAF – Gabriella Gustafson & Mattias Ståhlbom courtesy of http://hovercraftdoggy.com/.
My only question is how you could get this past most of the building inspectors I have dealt with.
UPDATE: Luc sent a comment and link to “miller’s stairs” (see comments) for tight spaces: http://www.mier.be/realisaties/trap_1.html. I think that early american houses had more ladders in tight spaces, at least in the appalachians and the ozarks.