Simple HTTP server with Python
Simply run this from the command line and it will server the content of the current directory:
python -m SimpleHTTPServer 80
I recommend setting an alias for that and make sure that the port is always open from the internet. It makes it very easy to share stuff with friends temporarily.
Python 3
SimpleHTTPServer is gone in Python 3.
You can now use:
python3 -m http.server 8000