Definition: Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
Input: Question: is it 'a usual' or 'an usual'? 'A usual' sounds more correct in my head ('Today was a usual day.') than 'an usual', but u is a vowel. Which one is correct and why? 
Answer: Usual (pronounced /ju.u.l/ as in you) begins with a consonant sound and, as such, it should be preceded by a not an. As an aside, I cannot help but point out that the sentence Today was a usual day is not usually heard in regular conversation. Today was an unusual day is what one might hear, instead! Indeed, I rarely hear the construction a usual. The definite article is more commonly used, in my experience: That's the usual thing. In place of a usual, one would also be more likely to hear not an unusual: Today was a usual day / Today was not an unusual day This is a usual occurrence / This is not an unusal occurrence or This usually happens You are right in saying that a usual sounds weird. As speakers, we tend to avoid constructions which, though correct, do not flow easily from the mouth. In sum, the following are valid and commonly used alternatives: not [an] unusual the usual usually.

yes