Buy a package of fresh habanero peppers, (AKA scotch bonnets) and when your friend that brags about having asbestos taste buds comes over... take a bite of the pepper and dare him to do the same.
He'll cry like a little girl and you won't even get misty eyed.
The chemical in a pepper that's "HOT" is called capsacin... and it's only located in the inner membrane of the pepper. Well, the membrane is a thin layer, inside the hollow of a pepper, (A habanero is hollow, if you didn't know).
Now... at the bottom of the pepper, it comes to a tip, about the size of a pencil point. THAT'S THE PART THAT YOU BITE OFF. This part is solid, thus lacking the capsacin membrane that will f' up your buddy when you hand him the pepper for his turn to take a bite.
If you've never done this to someone... you'll laugh your ass off. The burn he will experience is nothing at first... but after 10 seconds or so, it lights him up... and continues to get worse. He'll probably end up at your sink, frantically trying to wash the burn out of his mouth. That's exactly what happened to my buddy from Equador during our weekly poker game. He couldn't even continue playing poker for at least a half hour. Tears were literally streaming down his face. But he deserved it... he was a "nothing's spicy to me" shit-talker.
Don't try this with any pepper other than the ones mentioned above... they're not as hot... so it ain't funny and doesn't work.
I know... I'm a dick.