Firefox has a cool extension called pyxpcomext that sticks a Python interpreter inside your browser!
So I extended the pyxpcomext example "PyShell" into something a lot more user friendly (it wraps the most common XPCOM stuff into normal Python function calls) and useful. You can access and read details about it here: http://code.google.com/p/juicedpyshell/
Now, what's the point of this, you ask?
Well, what this means is that you can write a Python program that can interact with your browser as you are browsing and even modify the page (sort of like greasemonkey, but in Python) or even "click" the browser to another page for you!
But that's still technology, how about applications?
0. Automation of repetitive browser tasks.
1. Automated test of your live web site if you are a web developer.
2. Sophisticated ad elimination.
3. I'm thinking of a history database that remembers not only the link, i.e. "www.cnn.com" but also the contents of a page. Don't you hate it when you browse to an article only to find it gone!
4. Python XML/HTML development. If you are writing a Python back end server then your python is generating HTML. Its pretty cool to just be able to write hprt(" <> My Header < /h1 >") in the Juiced Python Shell, and actually SEE the rendered HTML appear. Its just like the Python standard "print" command but understands html! This really speeds up the dev/test cycle.
But why not...?