More Examples

Run a statement as you would using python -c with py -c:

py -c 'a = 5; print(`a`)'
a

Alternatively:

py -c 'a = 5' 'a'
5

The argument of (-c) will run before the expression. In the rarer case that you need to run a statement after the main expression, you can use the (-C) flag.
Plot data you have access to from the command line using the pyplt alias:

alias pyplt='py -c '"'"'matplotlib.use(`Agg`); from matplotlib import pyplot as plt'"'"' -C '"'"'plt.savefig("output.jpg")'"'"
py '[math.sin(x/10) for x in range(100)]' | pyplt -l 'plt.plot(l)'

Fig1. - output.jpg

Download all the images from the front page of imgur:

curl http://imgur.com/ | py 'map(lambda _: _.attrs["src"].partition("//")[-1], bs4.BeautifulSoup(sys.stdin).findAll("img"))' | xargs -n1 wget >/dev/null 2>&1