I was wondering about X too. I mean there are like what; a page of X words in my dictonary. I would guess X mas, but I've already been told it's wrong. So here's a random one plucked from the dictonary:
Xylotomous: capable of boring or cutting wood.
Oooohhhh. Hey what? X is for Xylotomous has a nice ring. Another Cornelia episode perhaps.
Well, look at it this way, that word will help you guys with your SATS.
Hey wait I just remembered, wasn't there that fairy woman who made the heart, didn't her name begin with X?