Problem with Series.plot
The code snippet below raises an AssertionError from pandas because matplotlib tries to add a dimension to the index ndarray subclass.
No big deal, since i can do
pylab.plot(np.asarray(ts.index), np.asarray(ts.values) 

import pandas
import datetime
import numpy as np
values = np.arange(5.)
dates = [datetime.datetime(2009, 1, 1, 0, 0),
 datetime.datetime(2009, 1, 2, 0, 0),
 datetime.datetime(2009, 1, 5, 0, 0),
 datetime.datetime(2009, 1, 6, 0, 0),
 datetime.datetime(2009, 1, 7, 0, 0)]
ts = pandas.Series(values, index=dates)
ts.plot()

Here's the trace back:
Traceback (most recent call last):
  File "pandasplot.py", line 11, in <module>
    ts.plot()
  File "/usr/lib/python2.7/dist-packages/pandas/core/series.py", line 1189, in plot
    ax.plot(x, self.values.astype(float), style, *_kwds)
  File "/usr/lib/python2.7/dist-packages/matplotlib/axes.py", line 3783, in plot
    for line in self._get_lines(_args, **kwargs):
  File "/usr/lib/python2.7/dist-packages/matplotlib/axes.py", line 317, in _grab_next_args
    for seg in self._plot_args(remaining, kwargs):
  File "/usr/lib/python2.7/dist-packages/matplotlib/axes.py", line 294, in _plot_args
    x, y = self._xy_from_xy(x, y)
  File "/usr/lib/python2.7/dist-packages/matplotlib/axes.py", line 239, in _xy_from_xy
    x = x[:,np.newaxis]
  File "/usr/lib/python2.7/dist-packages/pandas/core/index.py", line 110, in __getitem__
    return Index(arr_idx[key])
  File "/usr/lib/python2.7/dist-packages/pandas/core/index.py", line 50, in **new**
    assert(subarr.ndim == 1)
AssertionError
