This is a 0.8.2 feature, but you can download it separately for older IPython versions.

Suppose that you need to send a "thank you" letter every once in a while, and it's always almost the same. You decide to create a template that you will reuse every time. (ok, a defect submission template is a more realistic example, but let's keep it simple).

First, create the template and store it into variable 'letter':

[d:/ipython]|9> jed letter.txt
[d:/ipython]|10> letter = !cat letter.txt
 ==
['Thank you $recipient.',
 'We really enjoyed your letter.',
 'Best regards, $myname']
[d:/ipython]|11> letter = letter.n
[d:/ipython]|12> letter
            <12> 'Thank you $recipient.\nWe really enjoyed your letter.\nBest regards, $myname'
[d:/ipython]|13> %store letter
Stored 'letter' (str)

Now let's try to render it:

[d:/ipython]|14> import ipy_render
[d:/ipython]|15> ipy
ipy_exportdb             ipython.kpf              ipykit
ipy_render               ipython.pyc              ipykit.zip
IPython                  IPython_crash_report.txt
ipython.py               ipykit.py
[d:/ipython]|15> render letter

...

NameError: name 'recipient' is not defined

Now let's define recipient and myname, and store myname so we don't have to provide it every time:

[d:/ipython]|16> recipient = 'Yucca'
[d:/ipython]|17> myname = 'Olli'
[d:/ipython]|18> store myname
Stored 'myname' (str)

Now we just render the final result and go:

[d:/ipython]|19> render lett
letter     letter.txt
[d:/ipython]|19> render letter
---------------> render(letter)
            <19> 'Thank you Yucca.\nWe really enjoyed your letter.\nBest regards, Olli'
[d:/ipython]|20>

The rendered result is also copied to your clipboard.

The template syntax used is Ka-Ping Yee's 'Itpl' module, the same syntax that is used elsewhere in IPython.