The ‘pack chair’ by designer François Azambourg is a conceptual product (with 5 working prototypes apparently) which is a chair that folds and rolls up into a tiny package. When you take the cloth chair out of the packaging, there’s a switch on the side. The switch activates an internal combustion of a two part liquid polyurethane foam which fills up the cloth chair and becomes rigid enough to sit on within seconds.

I don’t think you can return the chair back to it’s flat folded state once it’s “inflated” so to speak. The advantages of this chair are clearly in the shipping and storage prior to it’s use; in it’s package it takes up significantly less space than any folding chair.

designboom via ohgizmo