I had no idea until I read this post on Burnt Lumpia. Says its proprietor, Marvin:
In the Philippines, street food vendors can be found grilling marinated chicken feet that are playfully nicknamed "Adidas" (three toes = three stripes). Similarly, grilled chicken heads are referred to as "helmets," and pig ears are known as the ever-so-80's "Walkman". I'm not making this up.
He's got tips on picking the best chicken feet and a recipe to grill them up right.