Is it Mexench?  Frexican?  Mexifrenchican?  As the El Diablo combines Mexican tequila with French creme de cassis, these are good questions.  The first mention of the El Diablo occurred in 1946, when it was listed in a Trader Vic's book (Trader Vic's is better known for tiki cocktails).  I adapted this recipe from one I found in Imbibe magazine.

2 ounces resposado tequila (I like Herradura)
2/3 ounce creme de cassis (use one made in France)
Juice from 1/2 lime
2-3 ounces ginger beer (non alcoholic)

Combine all of the ingredients except the ginger beer into a shaker, shake as if you're possessed by you know who, strain into a chilled glass, and top with the ginger beer.

The details of the El Diablo are important.  Using reposado tequila, which is aged between two months and one year, gives you a subtly robust counterpoint to the slightly sweet creme de cassis.  You'll find creme de cassis, a blackcurrant liqueur, in other cocktails such as the Bourbon Renaissance.  The lime juice and ginger beer add a little spicy punch. You can drink the El Diablo while reading Dante's Inferno (a powerful book), listening to Sympathy For the Devil by the Rolling Stones or Devil With A Blue Dress On by Mitch Ryder & The Detroit Wheels (both are great songs), and/or watching the Duke University Blue Devils (I am one).

If you believe in the afterlife, when the time comes I will have a seat on the express train to hell.  Find me in the bar car.