I'm reading a book on it now and the history is that it was invented by some boys in the late 1800s that liked to play cards, but weren't allowed to for religious reasons. As a result, they ended up creating a game that is kind of like bridge (4 players where your partner sits across from you), but for dominos (a religious loophole). It is definitely more complex than I expected.
I'm not sure if anyone else on HN is from Texas and plays, but I'd love to hear any stories.