I, for one, hate sitting in chairs without arms. Additionally, many chairs have very small backs, which cannot be leaned on comfortably. This is where Portable Chair Modifications come in.
"Arms" with a vice or clamp on their ends , which can attach themselves to a chair's back, and chair-back extensions, which can clip on to the backs of inadequate chairs. They would be made of a light, but sturdy substance (perhaps layered cardboard?), and could be folded up for easy transportation.-- Lottere, Sep 01 2009 Won't work.-- MaxwellBuchanan, Sep 01 2009 ...why not?-- Lottere, Sep 02 2009 Might not work in your world, but in the world of "normgineering" I cobble together modular low-budget workarounds such as this out of foam, cardboard, and scrap wood all the time. "Within budget", that's my motto.-- normzone, Sep 02 2009 Naturally, you'd have different models for certain sizes of chairs. I was specifically thinking of the small hard-backed chairs commonly used in schools. I can't imagine that it would be easy to damage one of those.-- Lottere, Sep 02 2009 Here, here. A little vice grip on one end and you're in business.-- phoenix, Sep 03 2009 random, halfbakery