IPython -- An enhanced Interactive Python - Quick Reference Card
  ================================================================

  obj?, obj??      : Get help, or more help for object (also works as
                    ?obj, ??obj).
  ?foo.*abc*       : List names in 'foo' containing 'abc' in them.
  %magic           : Information about IPython's 'magic' % functions.

  Magic functions are prefixed by % or %%, and typically take their arguments
  without parentheses, quotes or even commas for convenience.  Line magics take a
  single % and cell magics are prefixed with two %%.

  Example magic function calls:

  %alias d ls -F   : 'd' is now an alias for 'ls -F'
  alias d ls -F    : Works if 'alias' not a python name
  alist = %alias   : Get list of aliases to 'alist'
  cd /usr/share    : Obvious. cd -<tab> to choose from visited dirs.
  %cd??            : See help AND source for magic %cd
  %timeit x=10     : time the 'x=10' statement with high precision.
  %%timeit x=2**100
  x**100           : time 'x**100' with a setup of 'x=2**100'; setup code is not
                    counted.  This is an example of a cell magic.