I took a math class at Cornell the second semester of my senior year. I had to choose between taking it, the 2nd class in very popular history series (the half I really wanted to take), and some other class I really wanted. The math class (408 - a senior level undergraduate course) was supposed to be a good way to wrap up a major at math.
Long story short, the course was a joke. Half the people there were education majors (with math/science emphasis) who could only argue emotionally, not mathematically. And so we spent 2 weeks "arguing" whether or not .9999... = 1 or not. Heck, during the final presentations one of the students was having mental orgasms during her presentation because her realizations (what she was presenting) was in fact the culmination of her 4 years at Cornell. The only problem was that these amazing revelations were basic geometrical facts that (I imagine) most of the math majors realized freshman year.
Anyway, this guy's blog entry brought all of that rushing back .EvolutionBlog : What is Infinity?
I do find infinity fascinating - I've got a book on it.