Not really gaming related, but very recently the OnlyOffice desktop editors got open-sourced (the online editors were for a while already, but a bit difficult to set up and a bit Freemium infested):
http://www.onlyoffice.com/blog/2016/10/ ... en-source/
http://www.onlyoffice.com/download-desktop.aspx (The Ubuntu 16.04 .deb package seems broken right now, but the PPA works great)
You might say, so what? I have LibreOffice (and Calligra Office on Linux), but this is interesting because it has great cloud integration (not really available in the two others) and uses a completely new code-base that is actually working great with MS Office documents (something that's only partially true for LibreOffice). And last but not least, the GUI is much closer to MS Office 2010 (and looks very modern), which will probably ease adoption from people used to MS-Office.
The document-server backend now also works without Mono (uses Node.js), so things should be easier to set up for collaborative document editing on your own web-server.