CapPython and Python 3.0, and eyebrow-raising applications

Dear Mark Seaborn:

Obviously you should send a note to the [email protected]  
mailing list [1] letting them know about this, even if it is a  
foregone conclusion that they don't want to make any changes to the  
language before the Python 3.0 release.

However, don't despair.  They could change their minds again.  Also,  
Python 3.0 is backwards-incompatible with Python 2, and so it will be  
at least a few years if not many years before people stop writing  
Python 2 code.  You have plenty of time to demonstrate the usefulness  
of CapPython in the context of Python-2.

How to do that, exactly?  What is the application of CapPython which  
would raise the most eyebrows and cause the most Python hackers to  
say "Hey, that *is* cool!"?

The web server that runs untrusted Python code is a fine start.  Any  
other ideas?

Regards,

Zooko

[1] http://mail.python.org/mailman/listinfo/python-3000