It seems like this thread might be the right place to post about a fourth cool pepper.
Although it's better known than the three peppers featured here, piri-piri has been a favorite for several years.
Saveur Issue 59 discusses piri-piri in an article on Portuguese grilled chicken. It's too bad that they don't link to the original article, or credit the article's author, but here is the link for the recipe.
http://www.saveur.com/article/Recipes/Grilled-Chicken-with-Chile-SauceTry this recipe and you will not be disappointed. Though it sounds as though you can imagine what this will produce, I found myself surprised at the finished product. This is one recipe that transforms the ingredients into something unexpected. It's one of the things I truly crave every summer because it turns out such a juicy bird. You must use bone-in chicken pieces, though. I doubt I have to remind anyone here on LTH of this, but boneless, skinless breasts will not work!
Since I am currently without a grill, I decided to satisfy my craving for piri-piri with a version of pasta fra diavolo made with the shellfish I get from my local fishmonger. To flavor the clam, mussel and tomato base, I added about a tablespoon of this sauce. I found this
Timorense sauce at Chaves Market in Fall River, Massachusetts. I hope that others will post pictures from Chaves, which is a source for all foods Portuguese.

The sauce itself reminds one of harissa, but with a strong lemony flavor that adds that
quoi je ne les sels.
My recipe: Saute a few cloves of garlic in Portuguese olive oil. Steam a few clams and mussels until they open. Remove from shells. Add some chopped plum tomatoes and a bit of the clam broth and warm the sauce. Just before serving, stir in Quinta d'Avo to taste. Taste first and then season with additional salt and black pepper, only if needed. Toss with pasta and sprinkle with finely chopped parsley. (No cheese, please!)

Here is a link to a recipe for another piri-piri sauce from Saveur, though they call for fresno chiles and a bit of ginger, which is not present in the
Timorense version.
http://www.saveur.com/article/Recipes/Piri-Piri-Sauce
Man : I can't understand how a poet like you can eat that stuff.
T. S. Eliot: Ah, but you're not a poet.