pandas appears to crash doing pivot table from 10 minute examples
pandas 0.11.0 installed with Python 2.7.2 using "pip install pandas" on fully patched mac osx 10.8.5, running in a virtual environment.  running any pivot table against any DataFrame create so for -- nothing happens.  pressing ctrl-c I see the latest lines run are:

```
422         while com._long_prod(sizes) >= 2 ** 63:
423             i = len(sizes)
```

--> 424             while com._long_prod(sizes[:i]) >= 2 *\* 63:
    425                 i -= 1

The problem is reproducible using http://pandas.pydata.org/pandas-docs/stable/10min.html and running:

from pandas import DataFrame, Series
import pandas as pd
import numpy as np

then running lines [97], [98], and [99] in iPython and Python native.

I can't see any way to debug or go further. 
