Naka-kon Kansas City, MO March 2-4 2007
is a convention in the Middle of the Midwest, now in its third year. It's run by the anime club of the University of Kansas.
I've attended the previous two years when it was a single day event in Lawrence, KS and then two days. Now it has been extended to three days and has relocated to the Hilton near the Kansas City airport.
The slogan that this move allowed them gave me a groan and a slight chuckle. "We're not in Kansas, anymore."
All in all, I'd say that the con is fairly average in style, and most of the crowd leans toward high school to college age. While that fact makes me sad, I do know of a handful of more mature folks from the group I talk anime with that will be in attendance.