One of the easiest ways to share code that you've written in Pythonista is to create a Gist on GitHub. You can do this directly from the built-in "Export..." menu and you don't even need a GitHub account if you select the "Anonymous" option.
After you've created the Gist, its URL will be in the clipboard.
So far, so good. But what if you want to try out a Gist that someone else has posted? Sure, you could copy its text from Safari and paste it into a new script, but there has to be a better way, right? Luckily, Pythonista's actions menu is extensible with your own scripts – so here is a script that lets you import a Gist from a URL in the clipboard:
https://gist.github.com/b0644f5ed1d94bd32805
Just copy it into a new script, rename it to something like "New from Gist" and add it to the editor menu in the settings. Voilà: now you can import a Gist from someone else with just two taps – no need to copy and paste or even open Safari. Enjoy!