Happy National Margarita Day
Today is National Margarita Day (it's also National Cook a Sweet Potato Day, but that's not as much fun to celebrate). The origin of the margarita isn't exactly known. There are many stories, but most place it some time in the '30s or '40s in Mexico or the southwestern U.S., particularly Texas (more info 1, more info 2). It's currently the most popular mixed drink in the U.S.
If you want a way to celebrate at home, my wife has two very good variants.
Irmarita
Beer Margarita