MultiIndex Bugs (may be related to failure of get_tuple_index)
Some examples given in documentation for MultiIndexing do not work.  

Namely, you cannot add DataFrames or Series of different sizes, and you cannot use reindexing.  This seems to be related to the fact that Index(list(index)) fails if index is an instance of MultiIndex.

> > > from pandas import *
> > > from numpy.random import randn
> > > arrays = [['bar', 'bar', 'baz', 'baz', 'foo', 'foo', 'qux', 'qux'],
> > >               ['one', 'two', 'one', 'two', 'one', 'two', 'one', 'two']]
> > > tuples = zip(*arrays)
> > > index = MultiIndex.from_tuples(tuples)
> > > s = Series(randn(8), index=index)
> > > s
> > > bar  one    0.173505416255
> > >      two    0.225232806724
> > > baz  one    0.0144614539266
> > >      two    -1.42139309132
> > > foo  one    0.252413552834
> > >      two    0.0597526924593
> > > qux  one    -2.12059192632
> > >      two    -1.16341432838
> > > df = DataFrame(randn(3, 8), index=['A', 'B', 'C'], columns=index)
> > > 
> > > s + s[:-2]

Traceback (most recent call last):
  File "<pyshell#192>", line 1, in <module>
    s + s[:-2]
  File "C:\Python27\lib\site-packages\pandas\core\series.py", line 45, in wrapper
    copy=False)
  File "C:\Python27\lib\site-packages\pandas\core\series.py", line 1282, in align
    return_indexers=True)
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 429, in join
    join_index = self.union(other)
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1388, in union
    self_tuples = self.get_tuple_index()
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1191, in get_tuple_index
    return Index(list(self))
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 57, in **new**
    subarr[:] = data
ValueError: operands could not be broadcast together with shapes (8) (8,2) 

> > > s.reindex(index=index[:-2])

Traceback (most recent call last):
  File "<pyshell#200>", line 1, in <module>
    s.reindex(index=index[:-2])
  File "C:\Python27\lib\site-packages\pandas\core\series.py", line 1336, in reindex
    new_index, fill_vec = self.index.reindex(index, method=method)
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1175, in reindex
    indexer = self.get_indexer(target, method=method)
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1142, in get_indexer
    target_index = target.get_tuple_index()
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1191, in get_tuple_index
    return Index(list(self))
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 57, in **new**
    subarr[:] = data
ValueError: operands could not be broadcast together with shapes (6) (6,2) 

> > > df=df.T
> > > df + df[:-2]

Traceback (most recent call last):
  File "<pyshell#195>", line 1, in <module>
    df + df[:-2]
  File "C:\Python27\lib\site-packages\pandas\core\frame.py", line 65, in f
    return self._combine_frame(other, func, fill_value)
  File "C:\Python27\lib\site-packages\pandas\core\frame.py", line 1432, in _combine_frame
    new_index = self.index.union(other.index)
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1388, in union
    self_tuples = self.get_tuple_index()
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 1191, in get_tuple_index
    return Index(list(self))
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 57, in __new__
    subarr[:] = data
ValueError: operands could not be broadcast together with shapes (8) (8,2) 

> > > index
> > > MultiIndex([('bar', 'one'), ('bar', 'two'), ('baz', 'one'), ('baz', 'two'),
> > >        ('foo', 'one'), ('foo', 'two'), ('qux', 'one'), ('qux', 'two')], dtype=object)
> > > list(index)
> > > [('bar', 'one'), ('bar', 'two'), ('baz', 'one'), ('baz', 'two'), ('foo', 'one'), ('foo', 'two'), ('qux', 'one'), ('qux', 'two')]
> > > Index(list(index))

Traceback (most recent call last):
  File "<pyshell#198>", line 1, in <module>
    Index(list(index))
  File "C:\Python27\lib\site-packages\pandas\core\index.py", line 57, in **new**
    subarr[:] = data
ValueError: operands could not be broadcast together with shapes (8) (8,2) 
