Innovations in iPython. Very interesting things happening with iPython - this is already becoming very similar to typical math environments like Maxima or Mathematica. At least if you install Sympy and such. The QT console worked for me after some tinkering and installing packages with Homebrew. However, I can't get matplotlib installed on Lion at all, something is still not working there, which is a shame - that would also be interesting with the pylab mode. Here's more about the QT console.