source: Clay T. Martin
A combination of chilies and other ground spices for making taco meat or marinades.

3 | tablespoons | Ancho chili powder |
2 | tablespoons | Cumin powder |
1 | tablespoon | Garlic powder |
1 | tablespoon | Onion powder |
0.5 | teaspoon | Black pepper |
0.25 | tablespoon | DeArbol chili powder |
0.5 | tablespoon | Mexican Oregano |
1 | teaspoon | Red pepper flakes (optional) |

Rub the oregano between your hands to powder it well. Mix all the ingredients and store for later use.
I usually make a lot at a time, 'cause I use it for lots of stuff. Just multiply up or substitute another unit of measure. Remember 3 teaspoons = 1 tablespoon. I also don't put salt in this because of all the different things I use it for. This way I can add the amount of salt suitable for the dish.

Ancho is a mild chili, you could substitute New Mexican or another mild.
DeArbol is much hotter, but what it brings is a smoky flavor, you could use a smoked paprika.
Add red pepper flakes (like you put on pizza) for the heat, the more the merrier.