OwnCloud?
That being said: I've found it very difficult to contribute to the project. I've had multiple pull requests languish for months. Currently, there are 10 open pull requests that have not been touched by the devs in months (some are from January and earlier).
However: don't let that stop you from trying to contribute! :)
I work at a school district in central Pennsylvania. All of our staff (teachers, secretaries, custodial, etc) use ownCloud as a backup and recovery solution.
We chose ownCloud because it allows us to keep confidential records on our own servers, something that Sugarsync, Dropbox, etc did not allow us to do.
Besides, the OP states he is looking for Python projects.
FWIW They seemed really nice.