Spacewolff - P2P marketplace for ads. Turn excess space into ad space.
Postacard - Text a photo to send it as a postcard for $3.
StickerRide - Let your car earn money through advertising
Felt for iPhone - Handwritten cards for the modern world
Grabb-It - Location-based ads on your Uber's window
NanaGram - Text your photos and we'll mail 4x6 prints to your Nana.