How are you running the server?
Have you tried something like this?
manage.py runserver 0.0.0.0:8080
From the documentation:
Note that the default IP address, 127.0.0.1, is not accessible from other machines on your network. To make your development server viewable to other machines on the network, use its own IP address (e.g. 192.168.2.1) or 0.0.0.0.
0.0.0.0 means: bind to all IP addresses this computer supports. So, as TheSingularity says, you'll then be able to access your Django app by entering the private IP address usually beginning with 192.168.*; which is not accessible from the Internet.