Port-A-Pint Beer Glass - $7.95
This summer, don't be caught short without a glass at a BYOB OMGBBQFTW party! Always bring your own portable beer glass - it sure beats drinking from those disposable cups any day. The Port-A-Pint Beer Glass from the NeatoShop opens with just a flick of your wrist: Link | More fun Glassware and Drinkware
i had one as a kid 20 years ago. it also had a cap to provent it from opening while in a bag etc