The coolest thing I have seen was on a cooking/food show. The waiter brought to the table a live cobra. He then gutted the heart in front of him, then served the beating, bloody heart to the customer.
Bottoms up!
I haven't delved into anything too crazy but would gross a lot of people out - tripe, kidneys (veal), liver (duck,chicken), veal tongue. I have no problem eating certain fresh meat and fish/seafood raw.
My favorite food that many people would not consider utilizing in the animal and eating is the marrow found in beef bones. Absolutely divine!
