I just downloaded the PayDragon app, and the "Discover" feature is one of the more intriguing aspects. I regularly look for interesting, convenient food, and aside from walk-bys, it's not all that easy to find in my neighborhood.

EDIT: In Manhattan, however, PayDragon only has one restaurant in the "Discover" category right now—it's Murray's Cheese, which might be delightful, but it's also somewhat far and not especially appealing.