I feel bad enough when I get a coffee in a paper cup and not in my stainless travel mug that I have forgot to bring/wash.
Adding insult to injury is the means to insulate the cup from your hand. This is either more paper in the form of a sleeve, a styrofaom cup in itself, a foam lined cup exterior, a foam sleeve, or an extra cup altogether.
A small tough folded and quilted inflatable sleeve with an elastic joiner to accomodate all sizes could be blown up, used, deflated, and folded back into a credit card sized space in your wallet.-- Giblet, Dec 23 2007 Inflatable cup holder Inflatable_20cup_20holderSame idea, different intent - though [stupop] notes the insulation possibilities. [phoenix, Dec 24 2007] Surely there needs to be two of these?
Also sp. sleeve; forgotten.-- MaxwellBuchanan, Dec 23 2007 doh accidentally added the word to spell checker and auto corrected.-- Giblet, Dec 23 2007 [+] ... can be used to keep your beer cold, too-- FlyingToaster, Dec 25 2007 no, but I want it cold when I get where I'm going. Note the OP didn't mention driving :)-- FlyingToaster, Dec 25 2007 Yay!Gonflable.-- skinflaps, Dec 25 2007 then it was an incorrect statement; I can count on the fingers of one hand the alcoholic drinks I normally have during the course of a year and still have one left over for signalling purposes.
[edit] I'm not that grouchy, I just couldn't resist posting "and still have one left over..."-- FlyingToaster, Dec 26 2007 random, halfbakery