Commercial Literacy

I am a pretty well-educated person and, beyond the books, consider myself intelligent, with-it, and at least basically literate in most areas of common knowledge. Now, however, I find myself in an awkward place, having my faith in my own general cunningness being tested by... television commercials. That's right, commercials have pushed me to the limits of what is known to me.

What is a hemi? Do I have to drive a truck or a souped up old sports car to know? I'm sure it has something to do with an engine because in the commercials, two trucks pull up to a stoplight (usually somewhere in the desert where there doesn't even seem to be an intersecting road) and one driver leans out the window and asks his neighbor, "That thing got a hemi?" The neighbor counters with some sort of smug "well of course I have a hemi" answer and promptly leaves the questioner in the dust as the light turns green. It's very impressive. I want a hemi. Until I have one though, I can assure you that I won't be engaging in any conversations with my stop light neighbors!