It's a little bit sad, contributing to an open, federated project like pump.io on a closed, proprietary system like github, but damn, it's a slick experience. Find a confusing bit of documentation, click 'Edit', make your change, write a commit message to explain and justify it, click "Save" to store your work, then one more click files a bug with your patch attached.

I've made wiki-edits that were more complex than that.