First post here! Cool site, never used it before.
My design comes from the perspective of a custom motorcycle manufacturer. People who would come into possession of these cards would be motorcycle enthusiasts.
This design takes the business card and turns it into a funnel that can be used for putting oil into a motorcycle, or any other fluids for that matter.
The card comes with a hole punched out of the middle and two perforated curved lines running almost from the center to the top and bottom of the card.
The user tears the perforations and twists the card into the funnel shape. It holds together when it is inserted into a circular opening (see the beer bottle pic)
I also tried to make a small nut and bolt holder for those fiddly bits that you always manage to loose, but it would require more time to construct.
Enjoy!