Today I was reminded of something I learned a long time ago, in México, as a matter of fact.
Every Spanish book I've ever seen says that "¿cómo?" is the way to ask someone what they said, in the event you didn't hear or understand them. Basically, it's the Spanish equivalent of "what?". And indeed it is. Nearly every Spanish speaker I've ever spoken to uses "cómo". But did you notice I said "nearly" every Spanish speaker?
In México, and in fact, Mexicans in general, or at the least all the people I know, tend to use "Mande" instead of "cómo". In fact, I think I was the only person in México saying "cómo". It became blatantly obvious very quickly.
I'll also add that several people have told me that although "mande" has a widespread usage throughout México, "cómo" is what you should really use, as it is in fact proper spanish.
If you find yourself wanting to sound "muy mexicano", then "mande" is definitely for you. It's an immediate indicator that you spent some time around mexicans. To my knowledge, this is exclusive to mexican spanish. You use it exactly the same way you would "cómo".
Hopefully this will save you from the deer in headlights look when you hear it. And if you want to impress your mexican friends or the mesero, don't hesitate to flex your spanish muscles and throw this word around.