The most common way to write this used to be Quiúbole. Now with the text message dialect, we can also see kiúbole. (I won't be writing it that way -- but I want you to understand it if you come across that form.)
In Mexico it is a fun little fillip (ornament) to tack on a "le" at the end of this, that or the other, for example "¡Híjole!", which is more or less the same as "¡Caramba!" (Oh gosh! or even "Jesus H. Christ!". Here's another one: "¡Párale!" which means "Stop that!". (Normally, "le" would be an indirect third person singular object but in these expressions it does not provide meaning -- it's a decoration syllable, similar to sticking "mal" into the middle of many sentences in German.) One of the best ones is "Hórale," which can mean "Sure, fine, go ahead" or, more commonly, "Get going, man."
"Quiúbole" is thus "Quiubo + le", which is "¿Qué hubo?" plus the ornament for fun. It is a relaxed greeting between family or friends. It's a greeting to be given later in the day with someone you saw in the morning, or a friend you just saw yesterday or a few days ago. Like "Hey how's it going?" or "What's new?" or "What's the latest?".