I've played with Python a little on my own, but never used it in the classroom (although, based on what I see at CS education conferences, if I had to bet what will succeed Java as the "dominant" language for introductory programming classes, I would bet on Python).

I did, however, spend a month of last semester teaching (and learning) Ruby, which as far as I can tell does everything Python does, plus continuations (although I think higher-order functions are easier in Python than in Ruby).