To get everything running: 

1. download bottle and install it http://bottlepy.org/docs/dev/
2. download pyserial and install it http://pyserial.sourceforge.net/index.html
3. plug in the arduino to your laptop and upload the Arduino code
4. run the python script in terminal (python browser_vis_serial.py)
5. enter in the localhost into the browser

This will pull up the web page that has the serial out from the arduino displayed. 
Add a potentiometer to A0 on the Arduino, or read in from a few inputs, and vis 
it all. Anything that you print from the Arduino code will be displayed in the browser.
Add graphs, or dots that move around! 

more deets: 

Uses bottle.py to set up the local server

browser_vis_serial.py reads in the arduino data, sends it through http.  bottle
converts python dicts into JSON. this script also feeds in the index.html

index.html - javascript to get the serial data and display it. 

simple_serial - the arduino script, just reads from one of the analog pins