Bpython

bpython is a fancy interface to the Python interpreter for Unix-like operating systems (I hear it works fine on OS X). It is released under the MIT License. It has the following features:

   * In-line syntax highlighting.
   * Readline-like autocomplete with suggestions displayed as you type.
   * Expected parameter list for any Python function.
   * "Rewind" function to pop the last line of code from memory and re-evaluate.
   * Send the code you've entered off to a pastebin.
   * Save the code you've entered to a file.
   * Auto-indentation.