Phrase borrowed (more or less) from TV's "Wheel of Fortune", indicating disrespect for someone's mental abilities. Since generally the contestants on Wheel aren't exactly Einstein, telling someone to buy a fucking vowel is about equivalent to "Get a clue, moron!"
You think the War on Drugs is working? Buy a fucking vowel!
President Bush wants to help the middle class, eh? Maybe he should buy a fucking vowel with his family fortune.
I went to the Bears game this weekend wearing my cheesehead, and the fans there were buy-a-vowel drunk. I couldn't even comprehend their pathetic excuses for insults.
This means that you don't exactly understand what someone is saying, and you'd like them to elaborate
PERSON A: "I have a friend who has a friend who's friend has a friend that has a friend that knows somebody who knows a guy who knows a girl who's girlfriend has a boyfriend who went to a really bad doctor who's doctor's doctor's doctor's doctor ate a BigMac and flatulated on top of his flatulence until he fainted"
PERSON B: "Can I buy a vowel?"
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).