Escaping a Python VM

So, I am working with a webapp which allows you to run arbitrary python code on it. This code is, however, sandboxed and stuff like trying to execute OS commands or to open URL connections is disabled.

So far my attempts have been quite skiddie-tier, since I'm not experienced with Python or with escaping sandboxes. So, do you guys have any ideas what I could use?

The standard library is gigantic and it is written in C. There's bound to be a bunch of security flaws.

P.S. I will post updates and answers to questions, as well as give out more details when needed. The OS is Windows, and it's running inside a Microsoft Drawbridge Console Host.

Already done:
http://repl.it/languages
http://mathcs.holycross.edu/~kwalsh/python/
http://labs.codecademy.com/
https://www.pythonanywhere.com/try-ipython/
http://www.compileonline.com/execute_python_online.php