I've been having an on again, off again intellectual war with my sixth grade class about whether or not you can call zero the middle of all numbers. I maintain that you cannot, since to call something the middle means that it divides something into equal parts, which, since there are infinite positive and negative numbers, cannot be the case; you can't call two infinites equal in the same way that two finites are equal. They maintain that you can call zero the middle of all numbers, since, see, there is a correlation between every positive and every negative number. Hence, equality! So, zero is the middle!
Frankly, it just tickles me that they find the discussion at all interesting. They keep bringing it up, too. I should spring some of the dialogues of Galileo on them, assuming the role of Simplicius...