I recently toyed with Twisted and found it extremely pleasurable and easy to implement a very basic gross file transfer utility. (That can actually sync complete directory structure).
This "app" is composed of a server and client scripts, you have to run the server script on the target computer and use the client as instructed.
The server will never overwrite an existing file or directory but will create transmitted directory structures as required.
I found this utility to be very very useful inside a QA lab or a development LAN where unauthenticated unlimited file/directory transfer tool is needed and there's no will to install ftp, samba etc...
Oh, make sure you have twisted installed before trying this.
On ubuntu that usually means: sudo apt-get install python-twisted
If you modify this to work on windows, let me know. I did this on Ubuntu.
Feel free to package this for whatever distro you fancy, if you find it useful.
Download it here:dirsync