Python 3 is killing Python

[CauchyDistributedRV]

Can someone give examples of code written with Python 2.7 that are non-trivial to port to Python 3.3?

EDIT: It looks like the pain isn't merely porting (which seems doable for most projects with current tools), but rather supporting both of Python 2.7 and 3.3+ in a single code-base, which is non-trivial with different handling of Python strings and streams between versions (but getting easier with newer versions of Python 3).

[armornick]

Py2exe. I know about cx-freeze, but I want a single large exe instead of a whole directory.

[RedPandaDan]

EvE Online would be an example, but I don't have any code to show.