Oops, try http://aditya.bhatts.org/2013/12/16/bringing-opendocument-to-the-web/ (the link text looks right both times, but the actual link above has extra text appended).
I'll be updating allthefil.es to ownCloud 6, soon. Maybe a test run tonight, to see how easy it is. Topical: ownCloud uses WebODF.