obviscating python code for distribution

[Littlefield, Tyler]

Hello:
Thanks all for your information and ideas. I like the idea of open 
source; I have a fairly large (or large, by my standards anyway) project 
that I am working on that is open source.

Here's kind of what I want to prevent. I want to write a multi-player 
online game; everyone will essentually end up connecting to my server to 
play the game. I don't really like the idea of security through 
obscurity, but I wanted to prevent a couple of problems.
1) First I want to prevent people from hacking at the code, then using 
my server as a test for their new setups. I do not want someone to gain 
some extra advantage just by editing the code.
Is there some other solution to this, short of closed-source?
Thanks,